Mercedes-AMG branches out with a four-seat grand tourer with bruising performance
Model Tested: GT63 4Matic+
Price £121,350 • Power 577bhp • Torque 590lb ft • 0-60mph 3.3sec • 30-70mph in fourth 4.5sec • Fuel economy 21.7mpg • CO2 emissions 256g/km • 70-0mph 45.3m
• Titanic, responsive performance is all you’d ever want in a GT
• Brilliantly judged ride and handling works equally well on road and track
We don’t like:
• Cabin borrows a bit too liberally from lesser Mercedes models
• Practicality isn’t quite on a par with the best performance GT cars
The past decade has been one of real developmental significance for Mercedes-AMG. The firm’s continuing ability to transform practically any of Mercedes’ relatively ordinary cars into bona fide road and track performance weapons – often to class-leading effect – continues to be the foundation of its success. Meanwhile, the brand’s association with a certain five-time Formula 1
world champion and his AMG-liveried racing car must also have played its part.
Very few cars of this size impart such confidence
Arguably of even greater significance than both, though, is the fact that, within the past 10 years, Mercedes-AMG has turned its hand to developing its very own sports cars. The SLS was the first such creation, first appearing in 2009 with its dramatic 300SL-style gullwing doors and naturally aspirated 6.2 V8 – and its successor, the Mercedes-AMG GT, arrived in 2014 to continue the two-seater sporting theme. Neither was derived from an existing Mercedes model; both were intended to represent the wider reaches of what Affalterbach can achieve when presented with a blank canvas and a generous R&D budget; and both have proved good enough to convince Mercedes’ top brass that AMG should even be involved in the engineering of non-AMG car lines.
However, AMG’s third in-house model, and subject of this week’s road test, is a different kettle of fish for several reasons. Welcome, then, to the imposing of stature and convoluted of name Mercedes-AMG GT 4-Door Coupé, a four-seat sporting GT designed to leave more than a whiff of Affalterbach on the turf of cars as different as the Porsche Panamera and Bentley Continental GT.
Being AMG’s first stand-alone model with four seats, this car should broaden the company’s model portfolio quite a bit – but if it’s a proper GT car, it’ll be necessarily different from the SLS and GT that have preceded it. Read on to find out exactly how different that means.
The arsenal of technology required to make a 5.05m-long, 2.1-tonne car handle like a smaller, lighter, lower-slung sports car takes some wrapping your head around. The GT 4-Door Coupé does without the lightweight spaceframe construction of its two-door namesake, instead relying on Mercedes’ MRA monocoque car platform – and that’s why it weighs so much, and why there is so much physics for all that tech to overcome.
Our GT63 4Matic+ test subject – the current entry-level derivative for the UK market – is powered by Affalterbach’s 4.0-litre biturbo V8 engine. The ‘hot-vee’ configuration of the motor’s twin turbochargers should be familiar, but the use of so-called ‘anti-friction’ bearings inside those turbochargers is new and helps to sharpen the motor’s responses. In the GT63, the V8 makes a peak 577bhp and 590lb ft, the latter spread from 2500rpm to 5000rpm. The upper-level GT63 S 4Matic+ derivative, meanwhile, makes fully 630bhp and 664lb ft. In either case, and true to form, AMG plainly hasn’t risked under-endowing its four-seater debutant.
The car deploys its firepower to all four wheels via AMG’s nine-speed multi-clutch transmission (in which a wet clutch in place of a torque converter helps reduce weight and inertia) while an electromechanically controlled clutch rallies torque from the permanently driven rear axle forwards as required.
The AMG’s suite of cutting-edge drivetrain and chassis technology doesn’t end there. There’s a torque-vectoring, actively locking differential at the rear axle; four-wheel steering as standard; active aerodynamics similar to those found on the GT R coupé; lightweight alloy wheels; and an electromechanical steering rack with a passive variable ratio. A multitude of drive modes and corresponding selectable traction and stability control programs (the latter dubbed AMG Dynamics) are also present to allow the driver to fine-tune the handling to a level that, AMG claims, isn’t possible on its lesser cars.
For suspension, V8-powered GT 4-Doors make use of a pseudo double-wishbone arrangement at the front and a multi-link configuration at the rear, along with air springs and AMG’s Ride Control adaptive dampers. Anti-roll bars derived from those of the GT R help reduce the weight of both axles.
On that subject, however, our fully fuelled GT63 weighed 2135kg on our test scales, with that mass split 54:46 front to rear. For perspective, the front half of it weighed 1155kg – 10kg more than an entire Volkswagen Polo. The BMW M5 we tested last year was almost 200kg lighter. Not the best omen for the car’s handling – but also not one beyond AMG’s established powers to recover from.
The door panels arch elegantly inwards to meet a dashboard dotted with Mercedes’ hallmark turbine air vents, and behind the busy spokes of a new multi-function steering wheel sits a 12.3in digital instrument binnacle ‘dual bonded’ to another, more central display of identical size. AMG might have done more to distance its latest ware from that of other Mercedes and AMG models, but the overall effect is convincing: sumptuously old world in part but simultaneously very cutting edge.
Less convincing is the fascia on the transmission tunnel, which is one of the few interior elements bespoke to the four-door GT. It’s inspired by the GT two-seater’s centre console and features the same embossed gearlever, but it seems a touch ugly and quite space-inefficient. There’s a broader point here: that while material quality is mostly excellent and the nappa leather conspicuously soft, switchgear remains an area in which Mercedes still trails the likes of Porsche and Bentley, whose fitments feel more robust and have a more tangible sense of perceived quality.
In the rear of the cabin, Mercedes’ steeply raked roofline eats into head room for taller passengers a little, although leg room is generous and the seats themselves comfortable. To accommodate three abreast, you’ll need to tick an option box, because as standard the GT63 comes without a central berth – or the ability to fold the asymmetric seatbacks down and increase the capacity of the car’s 461-litre boot.
The boot itself is an adequately commodious space big enough to carry four good-sized duffel bags, although a Panamera Sport Turismo would carry five and an M5 saloon perhaps six. As with all fastbacks, the opening is uniformly broad, although the lip is also stubbornly deep.
This is the new era of Mercedes, with a brace of 12.3in displays that sweep across the dashboard as part of a single unit. These are conspicuously slick displays, with graphics of unrivalled sharpness and a depth of colour rarely seen elsewhere. Each can show a range of data pertaining to navigation, media, telephone and the trip computer, although the one that replaces the traditional instrument binnacle can switch through three styles of gauges (Classic, Sport and Supersport). There’s also the facility to bring up dials displaying real-time torque and power outputs, as well as boost pressure and g-force.
Commands are given by either of the two thumb pads on the steering wheel or via a trackpad on the transmission tunnel. Although they’re mostly fine, neither worked quite as seamlessly as we would have liked, with the trackpad at times eliciting frustrating lags. A software update could be required.
AMG chief Tobias Moers says this 4.0-litre engine is now nearing the limit of its performance potential. Handily for him, on the basis of this road test – in the lesser of two available derivatives, let’s not forget – you have to question how much more power a four-door performance car could ever sensibly need.
With the car’s launch control program working well and the traction benefits of four-wheel drive very evident, our telemetry timed the 577bhp GT63 to 62mph in 3.4sec, with 100mph arriving after 7.7sec – a mere 0.5sec behind that of the Mercedes-AMG GT R tested in 2017. On a cool dry surface, the car’s getaway is fantastically crisp, as fresh waves of force then jolt the car forward with each successive gear ratio dropping the tacho needle right into the sweet spot of the engine’s power band. MIRA’s testing straights are a mile long, which was enough for the GT63 to surpass 170mph with a zeal that suggests the claimed 193mph top speed is either electronically enforced or quite conservatively estimated.
The car’s standard-fit cast-iron brakes well match this whirlwind of acceleration, biting crisply but without unnecessary assistance and eliciting barely a squirm from the chassis when worked hard. The GT63 duly pulled up from 70mph just 3.9ft later than its coupé sibling, despite tipping the scales at 2135kg – some 470kg more than the GT R.
The GT63’s outright performance potential is somewhere between mesmerising and intimidating to comprehend, then, although the car can serve up its performance in a more versatile fashion when you want it to. In fact, AMG’s twin-turbo V8 has arguably found its ideal home in the four-door GT. Such a supremely characterful engine begs to be wrung out (rarely, if ever, will you disable the sport exhaust) and works with a throttle response and lack of crankshaft inertia that belies the deep, barrelling soundtrack.
The closely stacked low to intermediate gears of this well-mannered nine-speed transmission also ensure the revs rise supercar quick with the throttle wide open; but so tractive is this twin-turbo V8 that rapid progress isn’t reliant on that style. Huge torque propels the car along in a high gear with enough in reserve for easy-going overtaking. Our test car needed less than three seconds to surge from 50mph to 70mph in fifth gear, which is comfortably brisker than the W12-engined Continental GT.
AMG has derived a kind of magic from its blending of four-wheel drive, four-wheel steering, torque vectoring and chassis electronics in this car. The GT63 is not as nimble as the two-seat GT but this really is the sweeter car of the two to drive and seems more within itself and in command of its capacities at any speed.
Although the suspension is switchable through three levels of firmness, they’re closely grouped and the fundamental set-up is juicily pliant. At the same time, there is a telling absence of roll or pitch for a car of such mighty dimensions, and what movements do occur are closely and quickly checked.
This provides a solid base for the steering – quickly geared, at just 1.8 turns lock to lock, and well weighted – to operate at its best. It alters the car’s course swiftly but with a natural feel and without any nervousness off centre. Undoubtedly, the four-wheel steering helps to keep the car on line at times, although you’d never know a process so sophisticated was operating behind the scenes. Off-camber crests barely trouble this chassis, and with the suspension in Comfort and the powertrain fully dialled up, it will carve securely along all but the smallest B-roads. Very few cars this size impart such confidence.
It’s a confidence that will, soon enough, have more experienced drivers going deeper into corners and harder out of them. Indeed, the GT63 is a difficult car to over-drive because it generates tremendous grip and traction, communicates its limits superbly and is inclined to oversteer neatly and predictably when those limits are breached and its driver aids deactivated. It exhibits the handling adjustability of a considerably lighter, simpler car and its mass seems to sit palpably closer to the road than in any of the traditional super-saloon cohort. The upshot is a drive as scintillating as it is benign.
Simply put, if long-striding cruising refinement is more of a priority than usable, accessible rear seats, you’re better off buying an S560 Coupé than this; not that AMG diehards would even contemplate as much.
The GT63 is far from raucous at a cruise, but our noise meter recorded 72dB at 70mph, which compares poorly with the 66dB the Continental GT recorded and is considerably louder than even an M5. No single source for this cabin noise is readily apparent, and it’s certainly not enough to hinder conversation, but AMG’s in-house models have always generated a pervasive blend of wind and tyre roar in addition to the thrum of the engine, and that’s the case here.
But if the GT63’s aural finesse is a touch below par, the same cannot be said for the manner in which it cossets its occupants. AMG’s Performance seats might look the part but the standard items, as fitted to our test car, are more than adequately bolstered and supremely comfortable, even if their massagers feel a bit as though you’re being poked through an aeroplane seat.
The car’s ride quality also belies the outward demeanour. There are occasional edges to be felt but they are softer and more infrequent than you’ll find in the CLS 53, and many other quick saloons besides. The car has a long-legged gait, and as one tester standing on a Welsh mountainside put it, you’d drive an M5 to London, but you’d drive the AMG all the way back to Affalterbach – and you’d enjoy every mile.
The GT63’s asking price is high but won’t come as a shock to anyone in the market for a car of these abilities. A sticker price of £121,350 makes it the best part of £5000 more expensive than what is arguably its closest rival, the Porsche Panamera Turbo. Residuals are competitive with the Porsche’s. They’re a way off being so compared with the most wanted six-figure exotic sports cars, but such is the way of things with more usable fast four-seaters generally.
Standard equipment is impressive. For the car’s £121k asking price, you not only get that mighty engine and impressive chassis but also AMG sports seats upholstered in nappa leather, multi-beam LED headlights, a Burmester surround-sound system, 20in alloys and plenty more besides.
The step up to the GT63 S requires an additional £14,200 outlay. That premium is made easier to swallow by the fact that along with considerably more power, you get even more sophisticated performance hardware, including bigger brakes, and the AMG Dynamic Plus package.
You should expect a pretty voracious appetite for fuel, but not a crippling one. Our test car averaged better than 20mpg, which, given how intensively it was performance tested, isn’t a particular black mark, and it also showed itself capable of a 30.1mpg moderate cruise.