Roadsters are supposed to be the softer, more relaxed alternatives to their coupe siblings, but we're not sure Mercedes-Benz sporting division AMG got that memo. An open-topped version of the epic Mercedes-AMG GT was inevitable, but that doesn't detract from the excitement that comes from the new Roadster's introduction.
Mercedes has further underlined its 911-chasing intent by revamping and extending the whole GT line-up at the same time. The most interesting new variant is the oddly named GT C (there's no official meaning for 'C', but it sits between the GT S and the GT R), which borrows the best bits of the hardcore GT R Coupe while keeping everyday usability - it's even available as a Roadster.
As before, power comes from AMG's bombastic twin-turbocharged 4.0-litre V8, which is mounted low down and far back in the chassis for balance - and it sends its considerable power to the rear wheels. The pick of the new range could well be the GT C Roadster tested here, which uses the GT R's sophisticated electronically controlled limited slip rear differential to help control its robust 557 horsepower. Still want that Porsche 911 Turbo Cabriolet?
Drool: that's what you'll potentially do if you spend too long drinking in the curves of the new GT Roadster, as it's simply gorgeous to look at. Don't get me wrong; the GT Coupe is beautiful too, but AMG's designers have managed to give the Roadster an even lither, more dramatic appearance. With the fabric roof in place (buyers can choose from red, black, or beige as standard), the GT Roadster's roof 'volume' is smaller than the GT's, making the Roadster appear smaller somehow. That only goes to emphasise its width and ludicrously low ride height.
The standard Roadster looks great, but for full effect you need to upgrade to the GT C Roadster, as that comes with wider rear bodywork (to accommodate the GT R's differential and four-wheel-steering system), subtly restyled side sills and jaw-dropping 20-inch alloy wheels at the rear - all models get 19-inch rims up front, though you can tell it's the GT C by the red brake calipers with AMG lettering on them.
Helping the Roadster further is the adoption of the GT R's 'Panamericana' front grille, a vaguely retro touch that adds 15 vertical chrome-plated bars to the large air intake, giving the nose real aggression. The good news is that it'll be standard across the whole GT line-up. As will the GT R's innovative active air management system. Using an electric motor, this opens or closes louvres behind the lower air intake in about a second, depending on whether the engine needs the cooling air or not. With the louvres closed, the GT cuts through the air in a smoother fashion with less drag.
In the conversion from Coupe to Roadster, the GT's body has been reinforced in several key areas, such as the side sills, dashboard, windscreen, and roll-over protection system, yet thanks to the use of a composite boot lid and other lightweight materials, the Roadster is only 55kg heavier. Unsurprisingly, boot space is less in the Roadster, holding 165 litres of luggage to the Coupe's rather more useful 350 litres. Pack light, we say.
And you'll not find much more room for oddments in the cabin, either. It's strictly a two-seat cockpit (as opposed the Porsche 911's '2+2' arrangement), and it's not what you'd describe as particularly spacious, either. 'Cosy' is a good word for it, especially as the two seats are mounted low down so the doors, rear bodywork and massive transmission tunnel cocoon you within. The advantage to that, of course, is little in the way of buffeting, even if there is a hint of a breeze at the top of your head at speed. The roof itself takes only 11 seconds to fold away and that can be done at speeds up to about 30mph.
Thankfully, the cabin quality and design make up for the lack of space. The bespoke AMG driving controls festooning the centre console are tactile to use and the perfectly sized steering wheel frames clear instruments. We note with pleasure that AMG is slowly moving away from a flat-bottomed steering wheel to a more round one - i.e. the way it's meant to be… The seats deserve a special mention, certainly the AMG 'performance' items. Some may find them a little thin, but they look superb, offer seemingly infinite electric adjustment, and really hold you in place through the corners. What's more, they can be fitted with three-stage neck heating ('Airscarf' in Mercedes-speak) and even climate control to keep your bum warm or cool as you desire.
How does it drive?
We could say 'just like the GT Coupe' and leave it at that, but there's so much to get enthusiastic about here. In reality, the whole experience should be overshadowed by the might of this mightiest of engines. It's special in all its installations, but somehow more special in the GT Roadster. Nobody sane will step out of the entry-level model and denounce its 476hp as 'not enough', but once you've sampled the GT C, with its 557hp and 501lb ft of torque (up from 465lb ft in the regular model) you'll not want to go back. For the record, the GT C comes with an official 3.7-second 0-62mph time and a top speed tantalisingly just four miles per hour short of the double tonne, at 196mph. And that standing start acceleration isn't difficult to reproduce thanks to easy-to-use launch control. As the seven-speed auto cracks through the ratios with barely a let up in the forces threatening to rearrange your internal organs, it'll never fail to blow your mind how quickly you get to a speed where it's prudent to ease up.
And yet, the GT C Roadster is much more than a high-speed dragster. Through all this it makes the most evocative sounds, thanks in no small part to the standard AMG performance exhaust system. You can leave it to its own devices, operating according to the drive mode selected, or you can press a separate button to choose between two settings. As standard it's civil at low speeds, while the sportier setting opens the pipes at all times, for a naughtily purposeful growl even at idle. As far as we're concerned, the latter should be the default position - except if you're going for an early morning flight and you don't want to wake the kids and neighbours, perhaps. Even so, with the roof up and a constant throttle at a cruise, the GT C is remarkably refined and easy to live with on the motorway. Though the wide tyres can make quite a racket if the surface is a little rough.
But there's a very good reason for having wide tyres, and that's to hold the road. And boy does it. The good things start with the rock solid brakes and electromechanical speed-sensitive steering, which uses a variable ratio steering rack across the range. In the GT C, it's even more direct, as this car comes with the GT R's rear-wheel-steering setup. At speeds below 62mph the rear wheels turn in the opposite direction to the fronts, making the car feel more agile and easier to manoeuvre at slow speed. It's astonishing how quickly this car turns from curve to curve up a winding mountain road, with no lag or slack in the system. At higher speeds, the rear wheels steer in the same direction as the fronts, which is to the benefit of stability. The best thing we can say about all this is that you don't notice it in operation, but you undoubtedly notice how much fun it is to throw down an interesting piece of tarmac, yet it never feels nervous on the motorway.
It's fair to assume that, with so much power, such wide tyres and relatively stiff suspension, the GT C Roadster will be a bit of a handful, but it isn't. Sure, press Race mode, turn all the systems up to 11, and it feels little short of a race car for the road, with breath-taking response and ability, but conversely, in its Comfort settings, it's really easy and friendly to drive (though it'll feel wide on a British B-road), with softer throttle response and a more compliant suspension setup. Saying that, the regular GT Roadster is more civil again, and better suited to a life where most driving is on regular roads at regular speeds. The GT C, however, is more exciting. The defining characteristic of the car is that it can feel really sharp and the rear end is mobile according to your right foot's movement, but yet it never bites you for playing with the limits of adhesion, as it's so well controlled and communicative. Other cars may set faster lap times, but few are as enthralling to drive at all speeds.
Should I buy one?
Hell yeah! Mercedes-AMG has, in one fell swoop, considerably expanded its reach with the GT, effectively offering seven different models for sports car buyers to choose from (three Roadsters and four Coupes - the GT R isn't available without a roof). That may not rival the choice a Porsche dealer can display, but it's closer than ever, and while the 911 remains a solid and more practical option, we reckon the AMG GT C Roadster is more exciting than any open car Porsche makes. Job done, AMG.