Mercedes-Benz GT63 vs Porsche 911

What's the difference?

The Mercedes-AMG GT 63 S 4-Door Coupe fulfils the brief for an ultra-fast, ultra-luxurious, four-door weapon. The theatre that surrounds it will be enough for some, and those that want to a have a serious crack won’t be disappointed.

The more things change, the more they stay the same. The t-hybrid might be an entirely new propulsion system for the 911, but the net result is unchanged – power, poise and performance on tap.

Note: CarsGuide attended this event as a guest of the manufacturer, with travel, accommodation and meals provided.

At a fraction over 5.0 metres long and just under 1.9 metres wide, the GT 4-Door Coupe is substantial, but an overall height under 1.5 metres sets up an aggressive stance that screams speed.

Fat guards are filled by dark 21-inch rims, and the low-set, bulging bonnet sits behind menacingly angular ‘Multi-beam’ LED headlights sitting either side of AMG’s now signature ‘Panamericana’ grille, looking ready to chew up and spit out lesser machines.

It has to be said that calling this car a four-door is a bit cheeky because technically it’s a hatch, and to my eyes at least the gentle rearward slope of the turret and large cargo door enhances the design’s understated power.

Inside is a sea of top-shelf nappa leather, with the twin-widescreen cockpit layout (two 12.3-inch hi-res displays) dominating the dash. Carbon-fibre is applied liberally (in the 63 S), and the grippy sports steering wheels and seats look and feel close to track grade.

Turbine-style air vents (four in the centre, and one at each edge) are now a Mercedes design signature (used in the back as well) and they combine with the brushed metal finishes around the broad centre console and on the pedals to deliver a sense of occasion and anticipation just sitting in the car. Fit and finish is flawless.

This facelift debuts a revolutionary exterior design that has completely reshaped the 911.

Just kidding. If it ain’t broke and all that. The front air vents and exhaust have changed, the former now an active intake system that deploys via vertical flaps, but elsewhere it’s largely evolution over revolution.

Instead, Porsche has focused most of the updates in then cabin. In here, you’ll find a new digital instrument panel, they’ve changed some of the levers and the steering wheel.

In true Porsche fashion, though, this new 911 mimics the older versions in that it's one of the more intuitive cabins you’ll ever sit in. Everything feels as though it’s exactly where it should be, and all feels entirely centred on the driver.

At surface level the GT 4-Door Coupe is a more liveable alternative to the GT Coupe, for blazing fast road trips, and obscenely rapid grocery runs. But the fact is it’s sooo much more practical than its two-door stablemate.

Space in the front is generous with storage running to twin cupholders in the centre console, as well as a modest glove box, decent sized door bins (with room for bottles), and a lidded storage box between the seats.

Connectivity and power options include 12-volt outlets, multiple USB ports and NFC (Near Field Communication) tech for easy Bluetooth and Wi-Fi connection of enabled devices.

Rear seat room is healthy. At 183cm I was able to sir behind the driver’s seat set to my position with plenty of leg and headroom to spare. Although anyone travelling in the rear centre position will have drawn the short straw, because the back seat is sculpted with bolstered positions for the two outer positions only.

A fold-down centre armrest offers more storage with a lidded box and a pair of cupholders and twin vents in the rear of the front centre console can be adjusted individually as part of the four-zone climate control system.

Hit the button, near the driver or on the key fob, to open the tailgate door and you’re presented with 461 litres (VDA) of cargo space, with the rear seat split-folding 40/20/40 to increase flexibility and liberate considerably more room.

There are tie-down hooks at each corner of the boot floor, an elasticised cargo net is included, and 12-volt power is provided.

Don’t bother looking for a spare wheel, the tyres are run-flats, and both GT 4-Door Coupe models are a towing no-go zone.

This probably falls under the ‘next question, please’ umbrella, given that, while the Porsche 911 is known for a lot of things, vast acres of space with loads of practicality perks just ain’t a part of its portfolio.

The new 911 measures a not-insubstantial 4533mm in length, 1852mm width and around 1294mm in height, and it rides on a 2450mm wheelbase. Luggage space is a paltry 135 litres under the bonnet, plus whatever else you can fit in your pockets.

There’s seating for four, should you not like the people you’re squeezing back there very much, but really the 911 is best enjoyed as a two-seat proposition – which is why you can also delete the backseat, should you wish.

It also weighs a minimum 1595kg, or up to 1745kg, but Porsche says the hybrid tech only adds about 50kg to the total kerb weight.

Yikes. Perhaps I wasn’t paying close enough attention, because the Porsche 911 range now suddenly seems very expensive.

In fact, it inspired some research. Some 10 years ago, in 2015, the Porsche 911 range kicked off at around $208,000. Today, though, you’re looking at more like $280,500 for the entry-level 911, and if you want this bahn-storming Carrera GTS, you’re looking at more like, deep breath, $381,200, before on-road costs.

If you want four-wheel drive, a cabriolet roof, or both, the price climbs from there, with the GTS range topping out with the Carrera 4 GTS Cabriolet listing at $437,900.

Now in Germany’s defence, the Porsche has gotten progressively faster and more powerful over the years, and that’s true again with the T-Hybrid version, but we’ll come back to the tech stuff in a second.

Outside, it rides on staggered alloys (21 inch at the rear, 20 inch at the front), and there are standard matrix LED headlights, vertical-mounted active cooling flaps, and you can have it as a hard top, a Targa roof or as a full Cabriolet.

The biggest updates (apart from the driving stuff, of course, occur in the cabin, where the 911 has now push-button start, and introduces a new digital dashboard, which defaults as a digital version of the old analogue setup. The screen is 12.6 inches, and there’s a second 10.9-inch screen in the centre cabin which does your phone streaming.

There’s also a BOSE Surround Sound System, 14-way adjustable comfort seats, and digital radio.

The V8 volcano generating this car’s prodigious power is the same all-alloy, direct-injected, 90-degree 4.0-litre (M178) unit used in the two-door GT coupe, in this case with dry rather than wet sump lubrication.

Its two turbos are located in the engine’s ‘hot vee’ to improve under-bonnet packaging and reduce the distance exhaust gas has to travel to reach each twin-scroll turbo, and that charged air has to travel to the cylinders (minimising throttle lag).

Maximum power of 470kW is available between 5500-6500rpm and peak torque of no less than 900Nm is delivered across a broad plateau from 2500-4500rpm.

The GT 53’s 3.0-litre in-line six-cylinder unit produces 320kW at 6100rpm and 520Nm from 1800-5800rpm, with an ‘EQ Boost’ starter-alternator unit between the engine and transmission adding an extra 16kW/250Nm.

Drive goes to all four wheels via a nine-speed automatic transmission, in the 63 S featuring a wet, multi-disc start-off clutch, and a conventional torque converter in the 53.

The ‘4Matic’ all-wheel drive system sends drive to the rear axle permanently, and the front wheels variably, with the torque split continuously adjusted according to conditions and driver input.

A new (or at least, massively altered) 3.6-litre petrol engine has been developed for this T-Hybrid, which combines with two electric motors to produce a total 398kW and 610Nm. It’s only available with Porsche’s very good eight-speed Porsche Doppelkupplung (PDK) automatic, largely because the brand admits it would be… well… unpleasant to drive as a manual.

Now, there is lots of magic at work here, and I don’t want to bore you, but the Porsche setup sees a lightweight 1.9kWh battery placed basically in the middle of the front axle, and a 12-volt battery now behind the front seat. Then, a tiny e-motor lives as part of the gearbox (it’s just 55mm long) and delivers up to 150Nm at low speeds to supplement the petrol engine.

It’s joined by what Porsche calls an “electric exhaust gas turbocharger”, which essentially removes the spooling time from the turbo, delivering instant power.

The aim of the game here is excitement, not efficiency, and the launch-control-aided spring to 100km/h takes just 3.0 seconds. And it somehow feels, and sounds, faster.

The latter being important, with Porsche aware that if the new powertrain didn’t sound good, "nobody would like it”.

At the time of writing, Mercedes-Benz Australia hadn’t issued Australian Standard combined cycle fuel economy figures for the GT 4-Door Coupe, but NEDC Euro standard numbers are 9.4L/100km for the GT 53 and 11.3L/100km for the GT 63 S. NEDC CO2 emissions for the combined cycle are 215g/km and 257g/km respectively.

Despite the GT 63 S’s stop-start system (with glide mode) and eight- to four-cylinder deactivation tech (available from 1000-3250rpm), over close to 280km of mainly open road driving on the launch program we saw a dash-indicated figure of exactly 16.0L/100km.

Minimum fuel requirement for both models is 98 RON premium unleaded, and you’ll need 80 litres of it to fill the tank.

Porsche in Australia is yet to lock in local fuel use for the Carrera GTS T-Hybrid, but international testing has it at 10.5-10.7L/100km, C02 emissions of between 239-244g/km. 

Those aren’t exactly Toyota Prius numbers. But again, that was never Porsche’s intention. The electric power on offer here is intended to improve acceleration, not fuel use.

It’s fitted with a 63-litre fuel tank, which should deliver a driving range of around 600km per tank.

Okay, so first up this is one fierce four-door, claimed to sprint from 0-100km/h in 3.2 seconds, which is properly supercar fast, and if you’re game and have a driveway long enough, able to blast up to a maximum velocity of 315km/h. Wow.

And behind the wheel it feels every bit of it. A flat-chat, launch-control assisted take-off narrowing your field of vision ever-so slightly and inducing an involuntary tensing of the abdomen.

The accompanying soundtrack is suitably ferocious, with a full-noise pass delivering a satisfyingly sharp spike on the decibel meter.

With 900Nm available from just 2500rpm there’s always an ocean of torque available, and by the time you’re into the upper rev range in anything above third gear you’re either headed for licence loss or the first corner of your favourite race circuit.

The nine-speed ‘MCT’ transmission in the 63 S features a (wet) take-off clutch and the big four-door puts its power down beautifully, the rear axle LSD and carefully tuned ‘4Matic’ all-wheel drive system seamlessly distributing torque between the axles and individual wheels able to make best use of it.

Slip into manual mode and the fun factor dials up a few notches with sharp and positive moves between ratios. But if you prefer leaving it in drive the transmission will sense what you’re up to and pick up ratios at just the right spot to keep things on the boil.

The electrically assisted steering delivers good road feel and the 63 S’s rear axle steering helps with precise and predictable turn-in on cornering.

The adaptive damping system helps keep this roughly 2.0-tonne weapon in check on twisting backroads, the optimal setting for our launch drive being engine, transmission, steering and exhaust turned up to 11, with the suspension in ‘Comfort’ mode. Spot-on.

A monster brake package comprises big ventilated discs (390mm fr / 360mm rr) with six-piston fixed calipers at the front and single-piston floating units at the rear. They wash off speed quickly and calmly time after time.

But dial things back to a less aggressive, more everyday mode and the ride comfort remains a stand-out trait. Even on big 21-inch rims the GT 63 S turns coarse-chip rural bitumen into a smooth carpet, with very little noise filtering into the cabin.

The front seats are super-supportive and comfortable for long stints behind the wheel and ergonomics are top-shelf with all major controls ideally placed and easy to use.

And if you want to get into the nitty gritty the AMG ‘Track Pace’ function in the Comand media system captures and analyses over 80 vehicle-specific data points as well as circuit lap times. Fun

Porsche did just about the Porschiest thing to ever Porsche in launching the 911 Carrera GTS T-Hybrid, in that we piled into cars in Melbourne, drove the many, many hours (well, it feels that long, at least) to the Phillip Island race circuit, beat the hell out of the cars on track and on the drag strip for several hours, then trundled back out on the road and drove them back to Melbourne.

The subliminal messaging here is pretty clear. This new 911 might have a new powertrain, but it can still deliver the road-track-road experience without breaking a sweat — or, more importantly, without breaking any expensive bits.

So let’s do this in order, shall we? On the road, this new 911 is every bit as sweet as it has ever been. Comfortable, quiet enough when you want it to be, and — save some road noise from those big wheels – quiet enough to let you forget you're driving something with one of Peter Dutton’s nuclear reactors hidden beneath its svelte metal work.

Mind you, that T-Hybrid powertrain will happily remind you of its presence every time you press the accelerator in anger, the exhaust erupting into life and the 911 genuinely rocketing into the future, but stay gentle with your inputs and this hybrid 911 is a genuinely comfortable, genuinely liveable daily driver.

Its split personality appears when you rumble out onto a race track though, where you quickly discover the electrified, and electrifying, Porsche is properly, properly rapid, both in a straight line or around Phillip Island’s fast and flowing circuit.

It’s so rapid, in fact, that it feels most closely related to a performance EV, like the Taycan. Of course it is louder and more engaging, but that’s the best way I can think of to describe the instant power on offer here. There’s no ICE-like lags or lumps in the way that 398kW and 610Nm finds its way to the tyres and into the tarmac. Instead it’s just this constant, savage flow of power that never seems to let up.

Porsche says this new powertrain is about 50kg heavier, but you’d need to be plugged into the race track like its the Matrix to ever feel it, with the T-Hybrid feeling lithe, grippy and athletic, aided by near-perfect steering, the best automatic gearbox in existence, and exactly zero roll through the body. In fact, the only thing that really moves when cornering hard in this new 911 is the driver, and I genuinely got out after several laps with a sore neck from trying to stay vertical.

Downsides? Well, it’s faster in a straight line (it will be some 7.0m further down the road after 2.5sec when compared to the older GTS) and faster around corners (8.7sec faster around the Nurburgring than its predecessor), but there’s something delightfully analogue about the outgoing car, which also manages to feel more aggressive under heavy acceleration, too, owing to the little ebbs and flows of power, and after driving both back-to-back, I still can’t decide which one I like more.

This 911 arrives without an avalanche of active safety kit, but the key stuff is covered. There are airbags up front for the driver and passenger, side impact protection including thorax and curtain airbags, auto emergency braking (AEB) with pedestrian detection, a surround-view camera with parking lines, lane change assist, lane keeping assist, adaptive cruise control and a driver fatigue monitor.

Mercedes-Benz covers its AMG range with a three year/unlimited km warranty, like the other two members of the German ‘Big Three’ (Audi and BMW) lagging the mainstream market where the majority of players are now at five years/unlimited km, with some at seven years.

On the upside, Mercedes-Benz Road Care assistance is included in the deal for three years.

Service is scheduled for 12 months/20,000km (whichever comes first) with pricing available on an ‘Up-front’ or ‘Pay-as-you-go’ basis.

For the GT 63 S pre-payment delivers a $1230 saving with the first three services set at a total of $6450, compared to $7150 PAYG. Fourth and fifth services are also available for pre-purchase.

The 911 Carrera GTS is covered by a pretty underwhelming three-year, unlimited-kilometre warranty, with servicing required every 12 months or 15,000kms. We don’t have the hybrid service pricing yet, but as guide, the last 911 split the services into minor and major, and charged either $785 or $1285 for each.