Mercedes-AMG GT C Roadster 2017 Review

You can just bury any cynicism you might harbour about the GT C Roadster. It’s not just an opportunistic hack at the roof pillars with the gas axe to make a new car. It is so much more complete than that; it’s on the cusp of brilliance.

It’s evident from the first few hundred metres that this car is integrated and organised, and that AMG is telling the truth when it claims it was designed and engineered at the same time as the GT Coupe.

The car’s body feels rock-solid, stiff in the chassis but capable of riding smoothly and comfortably on its springs. It’s also breathtakingly fast, brutally loud at times and confident in its handling.

You would normally expect a significant deterioration in handling sharpness when a car moves to a roofless layout, but AMG has countered that by giving the GT C Roadster plenty of reinforcing and, just as critically, a big dose of hander helper in the form of the GT R’s rear-wheel steering system.

And it’s good. It’s charming and fast and noisy and crisp in its handling and rock-solid in the mid-corner exchanges. It’s fleet of foot, it changes direction quickly and assertively and its grip on the road instils its drivers with unshakeable confidence in the car beneath them.

The real beauty of it is that while you enjoy the best of the GT R only on a race track and the best of the GT C Coupe up close to its limits, you can enjoy the Roadster for a lot more of the time.

From the sunlight and birdsongs pouring through the open roof at low speeds all the way through to high-speed highway bursts and mountain-bend attacks, the GT C Roadster does its best to make the driver smile, and smile often.

It’s not just a warm-weather car, either, with heated seats and the airscarf warm-air vent integrated into the headrests of the seats, optional ventilated seats (maybe) and the option (yes, for sure) of a small, glass wind-stopper that slots between the rollover bars to stop turbulent air hitting people in the backs of their heads.

It’s very comfortable with the roof down at high speeds and it’s only at around 160km/h that voices need to be raised for conversations. The roof is a doddle to drive, as is just about everything else inside the leather-and-Alcantara cabin.

There’s a tiny glovebox and tinier door pockets but a surprisingly big centre console bucket, which also includes USB connectors.

The driving position is unusually straight (most car-makers like to tilt drivers slightly towards the middle of the car for intuitive reasons) and AMG keeps the seat controls down on the side of the seat, not on the doors like the parent company now prefers.

Its wider audience means it can deliver engagement at speeds other than flat out, and it can do that because it is in no way an afterthought.

All of this goodness begins with a core that is stupendously rigid in its bodyshell, thanks to AMG thickening up the walls of the hollow sills and filling them with more boxed-off chambers.

The biggest rigidity win is the cross-member (complete with the rollover protection system) behind the two seats, but significant gains are also made by introducing a new support brace between the windscreen’s frame and the dashboard and another one between the roof and the fuel tank.

Depending on the specification, it is about 50kg heavier than the Coupe, and AMG has done well to keep it to just that much. It’s no featherweight at 1660kg (DIN), but it’s far more coherent than just being a life-support system for a 4.0-litre twin-turbo V8.

The only real downside to it is that its legal maximum payload on top of a car with a full 65-litre fuel tank is just 205kg. That’s just enough for two burley blokes and a bottle of water. A small bottle.

They’ve gone to some extraordinary lengths to keep the weight low, including stuff like using magnesium and aluminium in the folding roof’s structural pieces, plus giving it a carbon-fibre/plastic boot lid.

The Z-fold roof system itself is fabulous to use in the real world. It consistently rises or falls in 11 seconds and it can go either way at up to 50km/h.

There is also the entry-level GT Roadster, but the GT C Roadster has it covered for everything significant.

Instead of the base car’s 350kW version of the 4.0-litre biturbo V8, the GT C has 410kW, which is actually 26kW more than the GT S Coupe and only 20kW shy of the GT R’s hard-core motor.

It hammers to 100km/h in 3.7 seconds, ripping through to a 316km/h top speed – all with the roof down.

It gets its mid-level shove thanks to 680Nm of torque from 1900rpm to 5750, it combines all of this with a seven-speed dual-clutch transmission and it remains true to the GT family’s rear-wheel drive beliefs.

And it’s fun. It’s great fun when it’s cruising along at low speed, with the motor burbling happily. It’s even fun when you’re cruising for hundreds of kilometres in traffic trying to catch a plane. It’s even more fun when it’s being flung at corners with abandon.

The GT C version has a lot more going for it over the entry-level GT than just a stronger version of the same engine. Its rear-end is 57mm wider, to accommodate the 305/30 R20 rear rubber. It uses an electronically controlled locking differential (the standard car uses a mechanical unit), it has rear-wheel steering, adaptive damping, the loudest exhaust system, bigger brakes and even a Race mode.

And it justifies a Race mode, because it’s good enough to frighten some poorly driven GT S coupes on the track.

None of this stupendous performance should frighten anybody off it, though. We found the car to successfully walk the line between being predicable and easy to control in corners and being dull. It’s never dull.

Instead, it can be flung into medium- and high-speed bends with just a hint of a push at the front, or you can be a bit wilder and provoke a tail slide if you dare.

Either way, just a fraction of a second later, the rear-wheel steering and the diff start to do their thing and pull the whole car back into line again, leaving it to corner flat with brilliant body control and punch out the other side of the corner superbly.

The rear wheels turn in the opposite direction to the front wheels until 100km/h, when they switch to turning the same way. It sounds all tricky, but it is well-proven technology and all you actually feel from inside the car is more agility and security.

It doesn’t take long before you trust it implicitly, convinced that it will never make you feel nervous about what’s happening underneath you, never a time when you think it might snap away.

High road crowns, shifting cambers, sudden drop offs, none of it phases the composure of the GT C Roadster, and the steering is quick to react and its feedback feels more interesting and nuanced than it does in the coupe. It’s user-friendly without being boring, and its grip levels are class leading.

It has enormous brakes, with 390mm discs and six-piston callipers up front and 360mm units (with a single-piston calliper) at the back, and five driving modes.

There are also 402mm carbon-ceramic front brake discs as an option, but we never unearthed a scrap of inadequacy in the standard units, so don’t bother unless you’re obsessed with track work.

It’s at its calmest in Comfort mode, and apart from some square-edged impact hits and expansion joints vertically at the rear end, it’s comfortable enough to call home for hours on end.

It even “sails” with the engine disengaged from the transmission on descents to improve its fuel consumption (which, at 11.4L/100km for the NEDC and 259g/km of CO2, is frankly a bit indulgent, but then indulgence is the entire idea behind the car).

Its Sport mode livens things up, making the entire car feel tied down a bit harder, while Sport+ lets it slide more, quickens the shifts, the steering and the throttle response and it even fires up the big-boy exhaust pipes. The Race mode gives the car more freedom to slide, bumps up the idle speed (so it can launch quicker) and shrinks the shift times from the brilliant gearbox even more.

There’s also an Individual mode that’s easily programmed through the multimedia screen, so if you’re staring through the screen at a bumpy mountain road, you can have the powertrain in Race mode and the suspension in the softest Comfort setting.

All of the settings have their own character, easy to distinguish and clear in their purposes. And because they’re so easy to cycle through, you find yourself switching between them frequently, just because they work.

Winding bits? Sport. Lonelier winding bits? Sport+ or Race. Calmer, gentle roads? Comfort. Group of schoolkids loitering on a footpath? Maximum exhaust noise for bangs and crackles.

The engine is never far from the front rank of thoughts for a GT C Roadster driver. Well covered in a myriad of AMG road tests before, the dry-sumped V8 buries its turbochargers in the vee created by the two banks of four cylinders, improving throttle response and cooling.

It’s strong at every point of its range, loading up early, bellowing deeply in the middle revs before peaking at a scream at 7000rpm. Then the transmission snaps out another flawlessly crisp shift and it does it all again.

It’s so flexible that it can be driven exclusively at low revs like a city hack, at medium revs to keep the car stable and calm in corners or at high revs, like it’s on a racetrack, and it will be equally comfortable and effective across them all.

It’s a bellowing beast of a thing with real potency and the chassis is so good that not a scrap of it is wasted on the GT C Roadster.

2017 Mercedes-AMG GT C Roadster pricing and specifications:
Price: TBC
On sale: July
Engine: 4.0-litre twin-turbo petrol V8
Power: 410kW at 5750-6750rpm
Torque: 680Nm at 1900-5750rpm
Transmission: Seven-speed dual-clutch
Fuel: 11.4L/100km
CO2: 259g/km
Safety rating: TBC