Affalterbach adopts plug-in hybrid tech for its most powerful production model yet

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When Mercedes-AMG was celebrating its 50th anniversary at the Geneva show in 2017, it unwrapped what then boss Tobias Moers introduced as only its third “autonomously developed” sports car (following the SLS and GT).

The name of the Mercedes-GT Concept wasn’t a great guide to its intended role within Affalterbach’s model range: it was to be the firm’s first four-door model. But what was most interesting about the car wasn’t its practicality but its powertrain. Rather than the hand-built V8 you normally associate with AMG, it had a performance hybrid powertrain offering four-wheel drive – and a little over 800bhp.

The pop-up spoiler emerges of its own volition depending on speed and selected driving mode, or it can be deployed manually if you’re craving attention in traffic

Six years later, both Mercedes and its performance outpost feel like different companies. But finally, the super-hybrid we were promised before we had even seen the production version of what would become the Mercedes-AMG GT 4-Door has now gone on sale.

Predating the more controversial new four-cylinder C63, the GT 63 S E Performance became AMG’s first- ever plug-in hybrid at market launch in 2022. It is nothing less than the most powerful series-production AMG road car yet made, and combines in-house-developed, high- performance battery technology with a hybrid drive concept unlike any seen elsewhere in the industry.

The Mercedes-AMG GT 63 line-up at a glance

With Affalterbach’s two-door sibling sports car off sale until the launch of the new-generation model later this year, the Mercedes-AMG GT line-up is currently greatly reduced.

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When the GT 63 four-door was introduced in 2018, it could be had in standard and S forms, but the lower-end version didn’t stay on sale for long. So today the choice is between the unelectrified GT 63 S, with its 630bhp, and this new E Performance hybrid range-topper.

Options include special paint finishes and leather upholstery treatments, an aerodynamic bodystyling kit and Mercedes’ Driving Assistance Plus package.

GT 63 S 4Matic+630bhp£156,415
GT 63 S E Performance831bhp£178,800


mercedes amg gt63s performance 4 door 16 headlight

Appearing as it did with a choice of mild-hybrid straight-six or turbo V8 power in 2018 (the UK market only ever got the V8 versions), the Mercedes-AMG GT 4-Door was a car styled to look like a stretched version of the AMG GT two-seater sports car: a key conceit of its design.

It was actually based on an adapted version of Mercedes’ first-generation MRA platform, which underpinned contemporary versions of the C-Class, E-Class and CLS. And so, while the two-seater GT has a lighter, stiffer, pseudo-spaceframe construction, the GT 4-Door is built around a more conventional passenger car monocoque.

You might not think the rumble of a charismatic V8 engine mattered in a car that’s just bumbling along, or idling at traffic lights, but when running without it, the GT 63 S seems bereft – and a bit pointless. I drove it in engine-on Sport mode almost everywhere.

The GT 63 S E Performance, then, layers its powertrain electrification on top of the regular GT’s mechanical package. It uses what is known as a P3-style hybrid drivetrain, different from the P4 layout of the likes of the Polestar 1 (where the combustion engine exclusively powers the front axle and electric motors the rear). 

And so the regular GT 63 S’s longways-mounted M177 twin-turbocharged V8 survives, as does its nine-speed multi-clutch automatic gearbox and mechanical 4Matic+ four-wheel drive system with electronically controlled limited-slip rear differential. 

Coming in is a 201bhp permanent magnet synchronous motor packaged with its own two-speed automatic transmission that drives directly into the existing four-wheel drive system’s rear differential. It all combines for 831bhp and 1084lb ft: powerful statements, both.

By disengaging the engine from the driveline at one end, therefore, the GT 63 S E Performance can run entirely electrically, with four-wheel drive – something no P4-style equivalent can do.

Electrical power for the motor is stored in what AMG claims to be the car’s chief technical innovation: its high-voltage drive battery. A compact and lightweight unit carried immediately above the rear axle, it has only 6.1kWh of total capacity.

But energy density is its trump card – and likewise the potential for the kind of rapid charging and discharging on which a high-performance electrified vehicle depends. A complex direct liquid cooling system, not of the battery casing but of every individual cell in the pack, enables it to weigh less than 90kg – but, according to AMG, to offer about double the energy density of most off-the-shelf battery technology.

While the E Performance hybrid system may save weight, of course, deciding to keep the GT 63 S’s V8 engine and mechanical four-wheel drive system certainly hasn’t. The GT 63 S E Performance weighed 2339kg on the proving ground scales: over 300kg more than the conventionally powered GT 63 4-Door we tested in 2019, and marginally more than the Polestar 1 we tested the year after.


mercedes amg gt63s performance 4 door 09 dash

The dizzying configurability of the GT 63 S E Performance hits like an anvil to the jaw as you look around its cockpit. This is indeed a proper four-seater GT, with adult-appropriate space in both rows, and those back seats can even be upgraded with an optional lounge pack, which adds heated cupholders and quilted, heated leather.

In the front, however, there is barely a square inch of available real estate – either on the raised, eye-catchingly chromed transmission tunnel, or any of the spokes of the steering wheel – that isn’t filled with some kind of secondary control switch.

AMG puts little displays in most of them, so as to make their selected condition and function plain. And there is at least a little intuitive hierarchy to the layout: the car’s primary driving mode toggle is closest to hand on the steering boss, mirrored by a configurable selector on the opposite side.

Cupholders are deeply recessed into the centre console and closely set. Try getting two coffee cups in and out without inadvertently removing their lids

The GT 63 S’s cabin is finished expensively but decorated very much according to the established modern fast-Mercedes playbook – ours having dark leathers, high-contrast, multi-coloured ambient lighting strips, and lots of glossy chrome, piano black and mirror-finish carbonfibre decor. In terms of apparent material quality, standards are high. Oddment storage is slightly tight, though. 

The boot evidences the packaging compromise of the battery, which robs more than 25% of the below-the-window-line luggage capacity of what would otherwise have been a more useful 461-litre space. What’s left is still enough for a couple of smaller flight cases, and few cars with such technical ambition don’t show some cabin packaging compromise somewhere.

Mercedes amg gt63s performance 4 door 12 screen

Multimedia system

Being one of Mercedes’ longer-of-tooth models, the GT 63 S E Performance uses an infotainment system with more physical controls than the latest Mercedes S-Class saloon: a tactile input device on the centre console and a row of shortcut menu buttons immediately above it. Though they are a little fiddly, having those permanent controls is still an aid to usability compared with a touchscreen-only system. The touchscreen cursor can also be controlled from the steering wheel spoke. 

Standard equipment is fulsome, with Mercedes’ customary twin 12.3in digital screens, a head-up display and Burmester premium audio (14-speaker, 640W of power, with Mercedes’ FrontBass woofers) included for no extra charge. The factory navigation system includes augmented reality directional cues, which are more distracting, and less useful, when presented on the central screen than they would be on the head-up display. 

Wireless device charging is included via a pad in the centre armrest, though it does tend to heat any phone left on it to concerningly high temperatures. We resorted to cable charging instead. 



mercedes amg gt63s performance 4 door 15 ngine

You expect audible drama when you hit the starter button of an 831bhp Mercedes-AMG – but initially that’s not what you get from this one. A synthesised electric pulse signals the readiness of the GT’s hybrid powertrain, and then, in its default operating mode, the car moves off quietly under electric power, and only rouses its V8 when you begin twiddling the driving mode knobs.

The breadth of ability that Affalterbach intended for the car, with operating modes ranging from Comfort and EL (for electric) at one end of the spectrum through to Sport+, Race and even Drift at the other, is vast. But, while the GT’s dynamic versatility is both ambitious and impressive in itself, it doesn’t take long to note some compromises in its fine detail.

The Track Pace app has race engineer-style boost deployment strategies developed at Affalterbach for well- known circuits around the world, which will tell you precisely where to let loose all of that electric torque as you lap. Sadly, MIRA’s dry handling circuit isn’t covered.

At low and medium speeds in Comfort mode, for example, you will notice occasional snatchiness from its gearbox and hysteresis in its low-speed throttle response (the hybrid system boosting strongly and suddenly as you tip into the power sometimes, but less so at others).

You will also notice quite a lot of high-frequency noise coming from the rear-mounted high-voltage electronics. Manifesting like a quiet and intermittent but nonetheless distracting high-pitched whining, it is unmistakably what an NVH engineer would describe as ‘noise’ rather than ‘sound’ – and certainly the sort of thing you would expect a luxury GT to filter out.

Select Sport or Sport+ mode and at least some of the V8 thunder you expect of an AMG super-saloon materialises. But when it comes, the GT’s combustion engine isn’t bristling with audible character. Hear it from outside the car, especially when close to the radiator grille, and it’s mostly made up of the whirring of belts and cooling fans and the sucking of turbos (although AMG’s sports exhaust makes it sound a lot fruitier from the rear).

On outright performance, of course, the car doesn’t miss the mark – it absolutely pulverises it. Needing only 2.9sec to hit 60mph from rest, 6.6sec to hit 100mph, 10.9sec for the standing quarter mile and just 2.5sec to get from 30-70mph through the gears, the GT 63 S E Performance beat almost every performance benchmark laid down by the five-star BMW M5 CS we tested in 2021. 

It feels like the savage it clearly is under full-bore acceleration: massively thrusty at medium crank speeds, always responsive and still reasonably free-revving beyond 6000rpm. Although, while it avoids any kind of peaky power deliver, it’s plainly a car propelled by a highly stressed combustion engine – not the fizzing, free-revving V8 of some AMGs.

Remain in the sportier driving modes, however, and the car’s oddest drivability quirk might be the way that it reserves what feels like half of the boost provided by its electric rear axle as a kind of ‘push to pass’ feature, the power accessible only by pushing the accelerator pedal beyond its kickdown detent. 

This might make sense if you want to make the driver feel like an F1 megastar on a qualifying lap, but the net effect on the road is really only to complicate the driving experience. On track, it makes the car more of a challenge to drive at the limit than it really needs to be.


mercedes amg gt63s performance 4 door 02 panning

The sheer weight of this car, the variety of roles it seeks to play and the intricacy of the hybrid powertrain needed to play them combine to clip its wings a bit when it comes to the driver appeal associated with the best super-saloons and GTs of the past 30 years. 

That’s a high dynamic standard by which to measure the car – but since it’s the most powerful road car Mercedes-AMG has built, you can’t help judging it through that prism. After the sensational performance numbers we have just recounted, it is the first meaningful way in which the shine starts to come off the GT 63 S E Performance’s driving experience just a little.

The adaptive air suspension makes the car’s ride gait range from medium-comfortable to medium-firm, depending on how it’s set. Body control is effective during everyday driving, with vertical and lateral movements only gathering to the sort of amplitudes to trouble stability or grip level at inadvisably high road speeds and on testing country roads – or on circuit. 

There is certainly decent touring comfort on offer here, then, together with plenty of ground-covering composure in objective terms. But there is little meaningful connected feel with the road surface; little of the oneness with the tyres that you need to gauge how hard each axle is working at any given time; and little consistency, too, about the car’s damping authority that might otherwise give you confidence at the wheel. For the last really great super-saloon we road tested, the BMW M5 CS, all were high points.

The GT 63 S E Performance steers fairly heavily and with surprising directness, but with only moments of useful tactile feedback. But despite the pace of that steering, the handling balance is a bit inert and nose-led in most of its driving modes, and it lacks the easy poise, natural agility and handling precision that entice you to explore just how adjustable and forgiving that handling ultimately is.

Mercedes amg gt63s performance 4 door 03 tracking rear 0

Comfort & Isolation

Most customers probably wouldn’t expect the GT 63 S to be as luxurious to drive as, say, a Bentley. Nevertheless, the lack of isolation applied to the car’s hybrid powertrain surprised all of our testers, with one in particular reporting annoyance with the high-frequency vibes it conducts after plenty of low-speed, electric mode testing. 

With the V8 running at a cruise, it is often quiet enough not to notice, but the GT 63 S recorded 70dBA of cabin noise at a 70mph cruise in any case – three decibels more than Bentley’s Flying Spur Hybrid at the same speed. It could clearly be more filtered for ride noise, and generally better mannered – as little as a typical AMG customer may care.

Front-row comfort for the driver is good but not exceptional, in seats short on adjustability in only one or two respects. On outright cabin space, a more conventional saloon would have greater head room, especially for adults travelling in the second row, but little better occupant space besides.

Track notes

Mercedes amg gt 63 s e performance track notes

Michelin’s Pilot Sport 4 S tyre isn’t the grippiest that Mercedes-AMG could have chosen. Keeping the car’s 2.3 tonnes on the dry handling circuit, while dealing with more than 1000lb ft and plenty of cornering speed, quickly became more than it could handle.

While Cup tyres might have coped with the heat created by the car’s weight and carbon brakes, the fitted PS4Ss didn’t. After two five-lap stints – and even after letting out excess inflation pressure – the front tyres indicated more than 100deg C, and our testing had to be cut short.

The car set a competitive lap time nonetheless. Running short on body control and cornering balance right at the limit of grip, its line could become ragged on corner exit, though mostly when feeding in power beyond the throttle pedal’s rather abrupt-feeling ‘push to pass’ threshold. The hybrid powertrain’s ability to keep boosting, even at sustained circuit pace, is very impressive.


mercedes amg gt63s performance 4 door 01 cornering front

If you’re spending nearly £200,000 on a four-seat super-hybrid GT, you are clearly not going to be motivated by the pecuniary factors that generally define the running costs of a PHEV. And in the case of the GT 63 S E Performance buyer, that’s probably fortunate – because this isn’t a car for extended electric-only running, or one that’s likely to save its owner many trips to the pumps.

With a battery pack designed for lightness and robustness of function during intensive driving, this car offers an official electric range of only eight miles, which turned out to be six miles in mixed real-world testing. That may be enough to run the odd urban errand without rousing the combustion engine, but fully electric office commutes are clearly unlikely. 

If you don’t like pop-up spoilers, add the AMG Aerodynamics bodykit (£3000), and don’t forget the Driving Assistance Plus package (£2100), which buyers will expect to find

The car has limited performance when running electrically, with 60mph possible from rest in a little over 10 seconds. Engine-off drivability is managed through a haptic accelerator pedal that resists further input at the margin of the electric motor’s performance, which works intuitively enough.

Had the EV range been greater, of course, we might have recorded better average test economy. As it was, we recorded just over 21mpg, compared with an ‘extended range’ touring economy figure of 23.9mpg: respectable enough for an 831bhp four-seater, but no better.


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Considered as an achievement of engineering, the Mercedes-AMG GT 63 S E Performance is a formidable piece of work.

For producing a plug-in hybrid powertrain with so much outright potency, but also such remarkable on-circuit stamina, we can only applaud Affalterbach. It’s something that none of its German rivals have managed – and that only its recent experience in Formula 1 could have delivered.

Perhaps it was inevitable that, in working to such a technical brief, some of its less tangible aspects would be overlooked. Or perhaps it was the breadth of character of a car designed to work as zero-emissions transport at one moment and as V8 hell-raiser the next that doomed the hot-rod charisma we expect to be frittered away or spread too thinly.

Even with a V8 on board, this car simply doesn’t entice its driver nearly as powerfully as an 831bhp Mercedes-AMG should. What it underlines is that multifaceted complexity is a poor substitute for true depth of flavour in a proper driver’s car. And, as it moves ever closer towards full electrification, that’s now a problem that Affalterbach must grapple with on a more meaningful level.

Matt Saunders

Matt Saunders Autocar
Title: Road test editor

As Autocar’s chief car tester and reviewer, it’s Matt’s job to ensure the quality, objectivity, relevance and rigour of the entirety of Autocar’s reviews output, as well contributing a great many detailed road tests, group tests and drive reviews himself.

Matt has been an Autocar staffer since the autumn of 2003, and has been lucky enough to work alongside some of the magazine’s best-known writers and contributors over that time. He served as staff writer, features editor, assistant editor and digital editor, before joining the road test desk in 2011.

Since then he’s driven, measured, lap-timed, figured, and reported on cars as varied as the Bugatti Veyron, Rolls-Royce PhantomTesla RoadsterAriel Hipercar, Tata Nano, McLaren SennaRenault Twizy and Toyota Mirai. Among his wider personal highlights of the job have been covering Sebastien Loeb’s record-breaking run at Pikes Peak in 2013; doing 190mph on derestricted German autobahn in a Brabus Rocket; and driving McLaren’s legendary ‘XP5’ F1 prototype. His own car is a trusty Mazda CX-5.

Mercedes-AMG GT63 S E Performance First drives