Mercedes-Benz AMG GT vs Mercedes-AMG S63

What's the difference?

The GT63 4Matic+ is a breathtaking example of everything that Mercedes-Benz and AMG are.

Ferociously fast, incredibly agile and superbly sophisticated, it should be on anybody’s shortlist, if that also includes a Porsche, Aston Martin, Maserati or even a Lamborghini. And it’s definitely much more than yesterday’s SLC ever was – for similar money in today’s terms, as it turns out.

But, around Tasmania’s glorious roads at least, the Mercedes-AMG lacks the ride comfort and road noise isolation to be a fully-rounded-out GT, and that’s a disappointment for a brand with such formidable history in making such cars.

Both of these vast vehicles are phenomenally comfortable - this is the kind of car that Mercedes does so well, and has done for decades. The S Class is rarely a disappointment but it's difficult to believe that such a big, heavy GT car can also dance the way the S63 does.

The S560 is far more weighted to being a GT - supremely comfortable with that active suspension, a growly, refined V8 and a cabin full of gadgets and comfort. The S63 is altogether more aggressive, to look at and to drive. Lopping the roof off both of them adds weight but, like any cruiser, also puts you out in the sun, the breeze and into your surroundings. Plus, in the case of the S63, you get more exhaust noise.

They're two very different cars and not just because of the engine. After all these years admiring it from afar, the S63 has delivered on my teenage expectations - fast, smooth and utterly mad.

This is still clearly a Mercedes AMG GT coupe, like the 2014 C190 original, but a ground-up redesign sees it subtly yet significantly altered.

Some 270kg heavier than before, the larger-in-every-dimension body combines aluminium, steel, magnesium and fibre composite materials for improved rigidity and a lower centre of gravity. Length (4729mm) and wheelbase (2700mm) have been stretched by 177mm and 70mm respectively. Width (1984mm) and height (1352mm) are also up.

The nose treatment is similar to before, especially with the bulgy bonnet and signature vertical slatted grille fitted. These, combined with the LED digital headlight shape effect, is reminiscent of, but far-better executed than, the goofy-looking MG5’s face.

Underneath, it's an all-new platform shared with the SL, with the rear transaxle of the old car replaced by a permanent AWD system, leading from 46:54 front/rear weight distribution to 50:50 as a result.

That aggressive, exaggerated cab-backward/ultra-long bonnet silhouette that visually connected it with the SLS gives way to more-conventional and practical coupe proportions that is striking if not especially original, since they do look quite 911-esque. Along with the longer wheelbase and wider tracks, the result allows for two small rear seats to be fitted, while liftback cargo access remains.

Similarly, in the name of way-more usable interior packaging, Mercedes-AMG says it pushed the driving position nearly 180mm forward compared to the previous GT. Let’s see what that all looks like inside.

The S Class Coupe is obviously related to the sedan but manages a svelte appearance. Slimmer hipped and with a more Coke-bottle shape, the Coupe - if you squint a bit - has a bit of the classic old pagoda about it. Obviously you can't do pillars that slim anymore, but the glass roof takes away some of the visual weight inside and out. 

The cabriolet's roof is nicely integrated and looks good when it's  up, which isn't always the case.

They all look long, though. It's obvious to see why the cars all run on 20-inch wheels - anything smaller would look hilarious.

The cabin is a fairly sensible re-imagining of the E-Class. The big twin-screen layout of the dash and multimedia system seems a bit more at home here. The chintzy Burmester speakers in the doors let down an otherwise classy cabin, which steers clear of otiose vulgarity in looks and materials.

The first impression inside is that of space, despite the falling roofline and coupe-like upsweep of the side windows and you look back. While, again, similar to a 911s, a kink at the door gives the GT a unique character.

Even larger people will appreciate the generous amounts of room up front, with space to stretch, sat in sumptuously comfy bucket seats. Note that the standard ones are better than the racier but firmer Sports versions.

The driving position is perfect, ahead of a dashboard that is very typical modern Mercedes in appearance and layout.

To that end, the tablet-style integrated touchscreen (11.9 inches) is clear, fast and intuitive once time is taken to learn it. And points are also won for the multi-configurable electronic instrumentation, that allows for a variety of screens, including track, classic and minimalist views.

The trademark turbine air vents, the quite beautiful material and trim finishes and just the general solid feel are further typical contemporary Mercedes cabin treatments, as are the excellent ventilation and ample storage options.

And while rear vision isn't great, that's what cameras are for. It's all pretty much on brand.

It is a shame, given how elevated the Mercedes-AMG engineering is underneath, that the GT’s interior look and ambience is so similar to those of a (albeit higher-spec) C-Class or GLE. It's simply not as special as some of the company’s previous sports cars.

More annoyingly, the ride is too firm and bumpy for a GT, and this has the unhappy effect of provoking random rattly trim sounds within the cabin. It’s a bit like scrunched-up cellophane. In a $420K (as tested) Merc, that’s very disappointing, especially as it can be heard over the copious amount of road and tyre noise droning through, particularly on coarser bitumen surfaces.

Further back, the rear seat is strictly two-plus-two, and nobody over 150cm tall is recommended to travel there by Mercedes itself. That sloping roofline is the culprit. That said, brief trips with a bowed head are possible, as the fixed cushions and split-folding backrests are actually surprisingly comfy. But only for short journeys. Kids should love it though, and the second row does open up the GT’s usefulness enormously.

As does a near-doubling of the AMG’s cargo capacity, jumping 146 litres to 321L with backrests erect, to a whopping 675L (+325L) in two-seater mode. The flat floor is accessed via a large electrically-operated liftback door, offering quite a large aperture for easy loading/unloading.

Having no spare wheel helps here, with a tyre inflation kit included in lieu of that.

Meanwhile, at the front, under the bonnet, things have definitely changed for the better as well.

Well look, if you end up in the back of the S Coupe, it's not a riot of space. Obviously it has back seats (the SL doesn't even squeeze a jump seat into its considerable length) but they're for occasional, if luxurious, use.

The boot is a reasonably decent 400 litres, obviously the cabriolet loses a few litres with the roof folded. Front and rear passengers will both enjoy a pair of cupholders and the whopping long doors will each hold a bottle.

One thing hasn't changed in nearly 20 years - the S isn't cheap. Available in coupe and cabriolet, the S560 starts at $314,900 for the former and $336,900 for the latter. Step up to the S63 pair and you'll pay from $370,500 for the coupe and $399,900 for the cab. If you're super keen for something spectacular, the twin-turbo V12-powered S65 is available for between $508,900 and $520,500, and features Swarovski crystals in the headlights, for some reason.

As you can imagine, there's quite a bit to cover, so for both cars I'll stick to the edited highlights. The S560s roll on 20-inch alloys, has a 590-watt 13 speaker sound system, digital TV, auto parking, active cruise control, panoramic glass roof, Nappa leather, active seats and power-closing doors.

It also comes standard with a heating pack that not only heats the seats but the steering wheel and centre console. In the cabriolet you also get the 'Airscarf' neck heater.

Both cars also feature's Mercedes' Magic Body Control with curve function. More of that wacky feature later.

The S63 AMG is a step up in power, price and spec. One notable change from the S560 is the loss of 'Magic Body Control', which is replaced with mere air suspension. The 20-inch alloys are 10-spoke forged units, the brakes higher performance composites with red calipers, while an AMG sports exhaust brings the noise.

Naturally, both are swathed in high-quality leather and feature dual-zone climate control, heated and cooled electric seats that adjust in every direction, deep carpets, keyless entry and start, fully digital dashboards and just about every gadget to which you can point your imagination.

Entertainment and sat nav are via Mercedes' 'Comand' system, which is displayed on a massive 12.3-inch slab of glass at the top of the dashboard. The 13-speaker Burmester-branded system is predictably impressive and with Apple CarPlay and Android Auto, you only have to use the basic software for the radio or various car controls.

There’s a plaque signifying which engineer “handcrafted” the GT’s engine – in this case, the famous M177 in 3982cc, 4.0-litre twin-turbo intercooled V8 petrol guise.

Delivering 430kW of power at 6500rpm and 800Nm of torque from 2500-4500rpm, it sends drive to all four wheels via a nine-speed multi-clutch transmission (dubbed MCT in AMG-speak), catapulting the GT63 4Matic+ from 0-100km/h in just 3.2 seconds, on the way to a top speed of 315km/h.

How does it do that?

With AWD, the GT is now nearly 15 per cent heavier than before, but it still manages a punchy 218kW/tonne. Active aerodynamics over, inside and under a more-rigid body structure also helps.

The AMG 4Matic+ AWD system goes from 50/50 front/rear, to 100 per cent rear, variable torque distribution according to conditions and settings, and backed up by an electronic limited-slip differential. Among the many driving settings are Race Start, Drift Mode and good-old Comfort, if it all becomes too much.

Also keeping all that performance in check is a high-performance composite brake setup with improved cooling for faster responses.

Interlinked active roll bars improve body control, the five-link independent suspension features adaptive dampers for a softer ride.

And, as for that 4WS tech, the rear wheels steer opposite to the fronts at up to 100km/h (by some 2.5 degrees) for tighter and tidier handling, or 0.7 degrees in the same direction above 100, for greater stability and road-holding.

Its effect on the way this near-two-tonne coupe zigs and zags around corners is something you need to experience to really appreciate.

All four coupes and cabriolets ship with Daimler's formidable 4.0-litre twin-turbo V8. The S560 scores 345kW/700Nm to drive the rear wheels through Benz's own nine-speed automatic. With all of that available, the S560 will crack the ton in 4.6 seconds and make a wonderful racket on the way.

Moving on to the S63, the same engine delivers a massive 450kW/900Nm. The run from 0-100km/h is dispatched in just 3.5 seconds and if I thought the S560 made a good noise, the S63 with its standard sports exhaust makes a better one. Again, Mercedes' nine-speeder is along for the ride.

Actually, the GT’s economy isn’t horrendous considering how fast it can go.

Even blasting a few times around beckoning country roads, we managed an indicated 13.0L/100km, which is an improvement on what Mercedes-AMG says the GT averages the 14.6L/100km average that Mercedes-AMG officially states.

That translates to a carbon dioxide emissions rating of 334g/km.

Using 98 RON premium unleaded petrol, an average of just under 480km between refills of the 70L tank is possible. The urban run sees consumption rocket to 21.8L/100km (for just 321km of range), or 10.4 out on the highway run, meaning that over 670km is possible should you decide to drive in a docile manner.

The lower-powered 560 drinks 98RON at the rate of 8.5L/100km for the coupe and 9.9L/100km for the heavier cabriolet.

The S63 ups the ante with 9.9L/100km for the coupe and an identical 9.9L/100km for the cab.

Our launch program contained some...er...spirited driving, which would explain the mid to high-teens fuel figures.

Nobody will drive the GT63 4Matic+ and think, ‘Oh, this is OK’, because its breadth of performance is phenomenal.

No matter which mode you're in, from Comfort through to track-tuned Race, the Mercedes-AMG blends forceful pace and commanding control without ever breaking a sweat.

Flex your right foot and the two-tonne coupe bounds into action like a giant on a mission, striding past posted speed limit signs in nanoseconds and way, way faster than the law will stand if diligence isn’t exercised.

And there’s no point relying on seat-of-your-pants sensations, either, because the chassis below embraces the road with an almost zealous devotion. Which is astounding, given how agile the four-wheel steering-enhanced handling is.

The 63’s super power is exactly that – it dulls your sense of speed. One tester admitted to exceeding 150km/h before noticing. An odd confession considering the sonic boombox that is the bi-turbo V8’s howl.

But jailbait performance is not even the 63’s most lingering joy. That would be its steering perfection, that delivers that rare trifecta of keenness, crispness and communication. The wheel feels eager and alive in your hands, even when powering between tight turns, backed up by sensational grip and control. How can a two-tonne GT handle so sharply?

Warm, dry roads were the order of the day, so we can’t tell you how the 4Matic+ permanent AWD system deals with wet or slippery surfaces, but the slick multi-clutch transmission, seamless torque-vectoring tech and sticky tyres more than cope with the 63’s formidable outputs.

So, that's the gushing part out the way, then.

Despite the adaptive dampers, rigid architecture and exquisitely sophisticated suspension, the ride is simply too stiff in Comfort mode, and downright jittery on some of the Tasmanian roads we tested on, for the 63 to be considered a true luxury grand tourer. It just isn't comfortable, luxurious or supple enough.

Plus, grippy as they are, the 21-inch wheels transmit too much road and tyre noise through to the cabin, meaning that the GT isn't as quiet as you'd hope. Add the aforementioned trim squeaks, and the expected cocooned silence isn’t always there.

The upshot is that the 63 possesses more of a sports car character than a luxury GT character. Great news if you're a 911 type buyer and are seeking a high-performance 2+2 alternative, but a disappointment if comfort and refinement are priorities.

Still, it is impossible not to be deeply moved by this Mercedes-AMG.

Let's start with the S560. That smooth V8 rumble is all you'll ever hear if you just slot into drive and go for a leisurely spin. The nine-speed automatic continues to be a revelation to me - in the GLC63 it's good and here, once again, it's excellent, finding the right gear for the occasion and riding the fat torque curve. Other nine-speed autos are not very good at all.

The test route for the S560 played to the strengths of the car. It had some lovely winding roads, which brought the trick suspension into focus - the Magic Body Control with curve function is hilarious. While the active suspension works hard at all times to ensure the ride is smooth and drama free, the Curve mode (no, really) actually leans the car into corners.

Those of you who remember the video game Wipeout 2097 will be big fans of Curve mode. As you approach a corner, you turn the wheel and then the car leans into the bend. This isn't active damping reading the road, it's the outside suspension lifting the car and the inside lowering it, so the car feels like it's gliding, like a hovercar. It's wild but oddly calming. Mercedes reckons it's great for those who get car sick. As I didn't have my wife on hand to test this theory - she chucks at the first sign of a corner - I couldn't verify this claim. That will have to wait.

The S63 AMG is a completely different proposition. The air suspension is more than up to the job of helping smother the effects of the car's considerable weight, meaning that no matter what you're up to, the car feels reasonably light on its feet. It never feels small, though, commanding the respect of the driver and plenty of space from other road users.

And boy, do you need some space if you kick the S63 into Sport mode. In true AMG style, the electronic reins relax and the big luxury coupe cheerfully kicks off. The tail will wriggle under an unsympathetic right foot, that signature V8 roar, crackle and hiss filling your ears. The S63 is always the harder-feeling car, but it delivers with a more sporting drive than the S560.

Being the generous soul I am, I volunteered to return the S63 to its home for the evening rather than consign it to the back of a truck. On the back roads I took to reach the highway, it was rock solid - fast, predictable and a lot of fun. Once I found the boring straight bits, it turned into a supremely comfortable cruiser, ticking along in ninth at the legal limit (and being Melbourne, it was very much the legal limit), dispatching overtaking with barely a flex of a toe. 

The active cruise took the stress of keeping away from the State Revenue Office's clutches while being quiet and utterly pleasant.

The S-Class coupe comes loaded with eight airbags, ABS, stability and traction controls, forward and reverse AEB with pedestrian detection, reversing camera, crosswind assist (I know, right?), traffic-sign recognition and reverse cross traffic alert.

The S-Class Coupe does not have an ANCAP or EuroNCAP rating.

What’s the GT like to own?

Mercedes-Benz offers a five-year/unlimited km warranty, with five years of roadside assistance. This is average for most mainstream and luxury brands, but superior to most sports-car makers like Porsche and Lamborghini.

Intervals are every 12 months or 20,000km, and while no capped-priced servicing is offered on the GT, pre-paid three-, four- or five-year service plans are available, ranging from $5165, $7700 and $8665 respectively.

Big performance demands big maintenance bills, it seems.

Mercedes offers a three-year/unlimited-kilometre warranty with roadside assist for the duration.

The company also offers both service plans (where you pay up-front as part of the vehicle purchase) and capped-price servicing on the coupes. Servicing over three years is in the order $2500.