Merc's facelifted roadster ushers in a new generation of turbo V6 AMGs, but dynamics hold it back against more sure-footed rivals like the Porsche 718 Boxter

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It is now almost half a century since a couple of Mercedes engineers decided to quit making cars and start making race engines instead.

Thus AMG was born. The firm soon branched out into unofficial performance mods for Mercedes’ road-going models, eventually joining forces with Mercedes to make the first factory-approved AMG model in the mid-1990s: the W202-generation C 36 AMG.

The ‘43’ moniker dates back to the early days of AMG’s collaboration with Mercedes-Benz

It was a marriage that would only ever lead in one direction. Mercedes parent DaimlerChrysler acquired a controlling interest in AMG in 1999 and the remainder of the company’s shares six years later, turning AMG into the wholly owned performance subsidiary we know today.

And what a busy outfit it has become, expanding from an output of vehicles believed to have numbered fewer than 10,000 units a year midway though the previous decade to more than 50,000 units a year now.

Mercedes-AMG, as it has become known, isn’t stopping there. Having ushered in some big-selling turbo four-cylinder models over the past three years, it’s now adding a range of turbo V6 options to sell alongside its range of full-fat ‘63’-labelled turbo V8s.

The first of them is this SLC 43.

The new top-of-the-line roadster has been introduced as part of a mid-life facelift for the car previously known as the SLK that, alongside the identity change, brings exterior styling tweaks, new cabin equipment and changes to the suspension, gearbox and engine line-up.

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In the UK, the range now consists almost entirely of four-cylinder models, running through 181bhp SLC 200, 201bhp SLC 250d and 242bhp SLC 300 until you reach the 362bhp V6 SLC 43.

So will swapping eight naturally aspirated cylinders for six force-fed ones suit a car tasked with perfectly splitting the difference between a cruising and a sporting brief?



Mercedes-AMG SLC 43 rear

This SLC roadster is an imperfect and slightly confusing way to introduce Mercedes-AMG’s new range of medium-hot ‘43’ models for one very good reason: it’s rear-wheel drive.

The similar-engined V6 saloons, coupés and estates due to follow it will all feature not just nine-speed automatic gearboxes but also all-corner 4Matic drivelines.

You get a bit of red trim on the engine cover — which is genuine aluminium, according to AMG. Doesn’t add much in my book

The cornerstones of AMG’s ‘43’ mini-brand will be defined as performance value, all-weather usability and decent real-world fuel economy. That’s largely virgin territory for AMG in every instance.

Nevertheless, the SLC 43 has the same twin-turbo 3.0-litre V6 engine that will power the upcoming C 43 Coupé and E 43 in saloon and estate guises, here producing 362bhp and 384lb ft of torque.

That’s gutsy enough for a 0-62mph acceleration claim of 4.7sec. The outgoing SLK 55’s V8 was good for 416bhp, 398lb ft and 0-62mph in 4.6sec – but the SLK 55 was also a £55,000 car and always felt to us somewhat overpriced and better endowed than its chassis truly deserved.

A subtle repositioning on price and a reappraisal of sporting ambitions were in order, then.

The new 43 engine, codenamed M276DELA30, is made up of six slightly oversquare cylinders in a 60deg V shape. Unlike AMG’s V8s, it’s not hand-assembled by AMG in Affalterbach but built at Mercedes’ main engine plant at Bad Cannstatt, Untertürkheim.

But the motor has been engineered by AMG and contains special internals and control software and dedicated injection, ignition and exhaust systems.

The standard SLC’s suspension is made up of multi-link arrangements front and rear. The body structure is a mix of aluminium and steel, with a folding steel roof powered by an electrohydraulic motor.

AMG’s overhaul involves the fitment of special firmed-up engine and rear subframe mountings, as well as stiffer steering knuckles, new wishbone guide bearings and forged track rods at the rear.

New suspension kinematics also feature, with more negative camber for all wheels.

Lowered, stiffened, passively damped sports suspension is standard on UK cars (with adaptive dampers to come), as is a mechanical limited-slip differential and an additional radiator.


Mercedes-AMG SLC 43 interior

Mercedes says the rationale behind the renaming of the SLC (née SLK) was to draw a clearer parallel with the sister model with which the car shares most: the Mercedes-Benz C-Class saloon.

However, it’s the previous C-Class to which the SLC bears a particular resemblance – and it’s something you don’t need any help to conclude after a moment at the wheel.

My better half loved the idea of the Airscarf, but years avoiding the business end of superheated hairdryers had her subconsciously leaning away from the headrest vents

It’s immediately obvious that Mercedes cabin design has progressed a very long way in the five years since the launch of this R172-generation car – and the SLC hasn’t benefited from that progress as it should have.

The driving position is a little too highly set to feel truly sporting, the centre console a little too low. The seats are comfortable enough and the material quality on show in all directions is very good.

But although Mercedes has done what it can to bring the car’s switchgear, instruments and infotainment system up to date, it still hasn’t quite done enough.

From the button-stacked centre console and the odd-looking, ashtray-sized storage cubby underneath it to the 7.0in multimedia display screen that is bigger than before but still not quite big enough, so many of the SLC’s interior fittings conjure a small but unmistakable sense of antiquation that it could do without.

Although Mercedes has expanded the SLC’s infotainment display screen from 5.8in to 7.0in in diagonal diameter, it still looks small compared with the screens currently being fitted by the competition.

As standard, you get the firm’s Audio 20 sound system with CD player, six speakers, Bluetooth audio streaming, DAB tuner and two USB ports. You get Garmin Map Pilot navigation as well.

As a multimedia offering, it’s just about generous enough in a £46,000 car not to look mean. However, for any proper smartphone integration, voice control, live traffic information or internet connectivity, you need to upgrade to Comand Online.

The Comand system gives you Mercedes’ own internet apps and in-car internet access for Facebook, internet radio, news and weather reports, as well as Apple CarPlay connectivity.

It’s not quite as sophisticated a system as it really ought to be, or as Mercedes offers in other models, but the navigation works well enough and mapping is displayed clearly and crisply. The optional Harman/Kardon stereo sounds good rather than brilliant.

Occupant space is good, even for larger people. You won’t find a great many places to stow smartphones, wallets and drinks, the door pockets being small and difficult to access, the glovebox shallow and the armrest cubby likewise.

But in a broader sense, there’s plenty of carrying space in the car and the boot is large enough with the roof up to rival that of a small hatchback.

The folding roof is simple to operate and completely automated. Lift and hold the covered switch next to the cupholders and the metal top detaches from the header rail, doubles over on itself and disappears neatly under the cantilevered bootlid.

Moreover, Mercedes has addressed two of the frustrations of the pre-facelift car by, firstly, allowing the mechanism to work while you’re travelling at low speeds and, secondly, by allowing the boot divider to close automatically before the roof slides back (assuming there’s nothing in the boot to prevent it from doing so).


3.0-litre V6 Mercedes-AMG SLC 43 engine

The Porsche 718 Boxster provides a ready-made yardstick by which to measure the objective qualities of AMG’s new V6.

The comparison isn’t quite perfect for our purposes; the Boxster was tested in dry conditions and the SLC in damp but drying ones, and that had plenty to do with the disappointing 5.5sec 0-60mph time the SLC posted.

You won’t find a plaque telling you which AMG engineer built your V6, because it isn’t made by AMG

But look instead at 30-70mph through-the-gears acceleration and you’ll see the Mercedes is marginally quicker than the Porsche.

Then again, so it should be. Given its power and torque advantages, in fact, you might have expected the SLC 43 to be faster still.

If you believe that any AMG worth its badge should be capable of blowing its competition into the weeds on accelerative punch – and since so many AMGs have done exactly that over the years, plenty of owners will – this one may come up short of your expectations.

The engine sounds potent enough: angry and waspish with the active exhaust set to its louder modes. And there’s nothing wrong with its style of delivery, which is responsive and nicely loutish in the lower part of the rev range but still builds in urgency as the revs rise.

In manual mode, the nine-speed automatic gearbox shifts smartly enough, will hold a ratio right to the redline if you want and generally feels more obedient than we’ve found AMG’s usual seven-speed ’box to be on occasion.

But in the SLC 43, that new V6 has a little too much mass to move: almost 300kg more than the Porsche’s flat four has to lug around. Given that the car never really feels viscerally fast in any of its nine gears, that weight penalty takes a toll.

For every SLC owner interested in the car’s outright pace, of course, there will probably be several who seldom venture beyond 4000rpm and are more interested in the power of the Harman/Kardon stereo than the biturbo V6.

This car is at least 50% cruiser, and its engine and gearbox are docile and slick in collaboration when the transmission is dumped in ‘D’. It’s well suited to the urban crawl and the motorway slog, too.

The hard-top is also better sealed against wind noise than a cloth roof would be and the active exhaust quietens down nicely in Comfort and Eco modes. It’s a shame, then, that refinement levels are compromised somewhat by a noisy ride, AMG’s suspension and steering bushings making for considerable road roar.


Mercedes-AMG SLC 43 drifting

As a keen driver, it’s a lot easier to find things to like about the SLC 43’s dynamic character, and what it does on a well-surfaced road, than it was with the SLK 55.

Muted and inert steering, overly firm and reactive body control, an unengaging balance of grip and intrusive stability control made this car’s predecessor a dish best served on someone else’s plate.

Torque levels don’t feel huge during steep climbs, but closely stacked ratios make it easy to find the optimum gear

The SLC 43 addresses at least some of those shortcomings moderately well.

Although it falls short of the dynamic standards needed to compete with the best sports cars in its class, it isn’t for want of effort from AMG.

The stiffer pathways engineered into the SLC’s front end and greater lateral forces conjured by those new wheel angles and suspension settings certainly pay a healthy dividend on steering feel and handling balance.

The directness of the steering is still considerable but, matched to plenty of reassuring weight and contact patch feedback, it’s no longer a barrier to your enjoyment of the car’s handling.

You can guide this SLC with confidence and even feel sure enough of the grip level up front to begin engaging the rear axle in your cornering routines, driving and adjusting the SLC on the throttle as and when you fancy.

The ride, however, can be a little crashy and aggressively damped with the current suspension set-up. If the vertical body control were defter and more progressive, it probably wouldn’t need to be so uncompromising, but as it is, the passive dampers allow a little too much initial unchecked deflection, only to suddenly and abruptly clamp down on it.

That unsympathetic ride tune also frequently asks too much of the SLC’s body structure.

Thumps and thuds that ought to be contained within the wheel arches are allowed to eddy outwards around the cabin, and some scuttle shake is evident over poorer surfaces with the roof down.

Smooth circuits suit the SLC 43 quite well — better, at least, than bumpy, testing B-roads. With good lateral body control and grippy and incisive handling, the car darts into corners keenly.

It demands a certain amount of effort through that weighty, direct steering but also rewards that effort by sticking determinedly to its line and carrying lots of speed.

Select Sport Handling mode on the ESP stability control and you’ll find it subtle and permissive, taking the throttle away only when it’s absolutely necessary and being understated with its braking interventions.

Turn the ESP off and, even in exaggerated slides, it’ll stay off — although the SLC’s blend of grip and torque means you need commitment to unstick the rear axle.

Mid-corner bumps can crash through the suspension and cause the body to shudder discouragingly; likewise hard-charged kerbs. But, overall, an SLC 43 would make a more entertaining track day car than an SLK 55, its steel brakes taking punishment robustly.


Mercedes-AMG SLC 43

A £9000 price cut is no bad place to start for this section, and that’s ostensibly what the range-topping SLC has had.

Some will argue that you’re getting a lower-order performance car here than you might have with the SLK 55, but we’d agree only in the narrowest of terms on out-and-out acceleration and certainly not in handling appeal.

CAP doesn’t expect the refresh to do much to improve SLC residuals, which lag behind rivals

The SLC 43 undercuts a 718 Boxster S, equivalent BMW Z4 and, it’s predicted, Audi’s upcoming TT RS Roadster.

Clearly, Mercedes’ commitment to performance value with these new 43 models is to be taken seriously.

If you are keen on a SLC 43 then we would recommend opting for the Comand Online infotainment and the Harman and Kardon stereo. Ignore the memory seats, illuminated door sills and the Magic Sky Control roof.

And how seriously should we take AMG’s commitment to fuel efficiency for this new breed of V6 models? With a pinch of salt, perhaps – albeit a very small one.

The SLC 43 averaged 26.5mpg on test and returned 33.0mpg on a touring run. That compares with 25.6mpg overall and 35.9mpg touring for the 718 Boxster.



3.5 star Mercedes-AMG SLC 43

Mercedes-AMG’s decision to create a range of more affordable V6-engined saloons, estates, coupés and roadsters to complement its V8s is great news.

The SLC may not be an ideal way to launch the ‘43’ sub-brand, but it does prove that AMG wants its lesser models to be exciting and engaging – no less seriously sporting for being a little more usable. Which we applaud.

AMG’s new V6 shows promise; SLC shows progress but mostly its age

It’ll take a while to get used to the idea of an AMG that’s a bit less vigorous than some of its rivals, of course, but although the SLC 43 meets your performance expectations more meekly than you might expect, there is more power to come from AMG’s V6.

The SLC 43 is easier to recommend to some, but tougher to most. Engaging handling gives it more dynamic appeal than any AMG SLK ever had but, in so doing, its creators may have compromised on what has made the car palatable as a laid-back cruiser. The SLC is also showing its age now.

As a result it falls short of the Jaguar F-Type V6, Audi TTS and the imperious Porsche 718 Boxster.


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 SLC 43 2016-2018 First drives