Mercedes-AMG launched its second-ever complete car in the UK two years ago. The GT two-seat coupé was a cheaper, less hardcore replacement for the awesome if boneheaded SLS, but it was still a bit of beast. Whenever I've seen a GT on the road, it's always been driven in a manner that suggests its owner doesn't actually know about speed limits, or his pants are on fire.
Now, as surely as night follows day, we get the drophead version, the GT Roadster. On sale this summer, it's available in two versions; the wimpy 470bhp £110,145 standard GT (which is £11,400 more than the equivalent coupé), or the 550bhp £139,445 GT C Roadster, which has a wider body to accommodate larger wheels, tyres and increased track, an electronic limited-slip differential and electronically adjustable dampers. Sharp-eyed GT aficionados will have noticed that there are two, maybe three, missing models here: GT S Roadster and GT C coupé, which are definitely on the way, and a Roadster version of the top model GT R coupé, which seems an unlikely prospect.
The speed limit on the interstate roads that cross the Arizona deserts where Mercedes hosted the launch last week have a maximum speed of 65mph. The GT C will get there from a standstill in about four seconds, with its 4.0-litre biturbo V8 hammering this 1.7-tonne car on to a top speed just south of 200mph.
At that point you might as well stop at the side of the road and burn your driving licence for all the use it will be after the Highway Patrol have finished with you. At no time, even when roads were lightly covered in snow in the mountains behind the old copper-mining town of Jerome, did the GT roadster do anything other than champ at its bit in anticipation of going ever faster.
Eventually we stopped just to admire it, as it ticked and tinkled while cooling in the evening sun. What a damn good looking car this is, with that bulbous grille (they call it 'Panamericana' after the eponymous race, but Mercedes's victorious 1952 300 SL also had anti-vulture windscreen bars after one smashed through the glass) and the fluted bonnet with its huge ducts clearly filched off a warship. Of the two models, the C version seems overly aggressive and of such breadth that road width restrictors will have a field day. There are few bum notes, but the rear bodywork is indistinctive and over-layered, especially when the boot spoiler bobs up and down like a talking post box.
Climb back in and you're aware of the tall sills. Doubtless there to stiffen the bodyshell, they also clean themselves against your trousers. There might be a modest way into the seats dressed in a short skirt, but you'd probably be better to practice out of sight first.
The cabin presents a suede, carbon-fibre and aluminium study in speed. From the twin-dial instrument binnacle to the rows of virtually identical piano-key switches, there's scarcely a sports-car cliché untouched.
Transmission tunnel as big as the Blackwall Tunnel? Check. Cartoon-like buttons running along the centre console? Check.
The seats are as unyielding as a regimental sergeant major's bark and there's a feeling you are sitting on top of the rear axle. There’s not much room, either, with a shallow console, small door bins, and a comedy glovebox.
Fortunately the boot, while shallow, is big enough for a couple of squashy bags more accommodating than the toothbrushes-and-knickers of legend. As we discovered later, other cabin trims are available, in fact there are 11 bodywork colours (Solar Beam yellow, as shown in the pictures, costs an extra £7,500!), three shades for the hood and 10 interior trim textures. You could let your imagination run wild, but one of the classiest options is simple gun-metal grey (Designo Selenite at £2,145), with a sail-cloth red hood and old-fashioned darkish leather with piano black highlights.
The V8 woofles into life until warmed, whereupon the stop-start system shuts it down leaving a noise-less vacuum that feels like someone switched the world off.
Rev it and it sounds like you pushed a couple of bricks into the final spin cycle of your washing machine. This car is all latent bombast and portent; it sends a chill down your spine.
And not without reason; my goodness it's got some go. Floor it from the standstill and, if not Tesla quick, it's more than capable of leaving your tummy precisely where you started out. The acceleration never seems to ease; past 100mph and beyond, you feel as pressed into the seat as when you first smoked away.
Even the 470bhp standard GT does this, but it also has a less abrupt throttle action and is easier to control at low speeds. The seven-speed automatic gearbox has AMG's own clutch pack in place of the torque converter. It's annoyingly clunky when you want to creep around town, but no complaints of slip, slush or lack of moral fibre when you're on it like jam on toast.
Switch off the traction control and the handling is less lairy than you might expect, but on a wet road you need a surgeon's delicacy
You need to be careful, however, with both engine derivatives, as the violent power delivery quickly overcomes the tyres' grip and the traction control is effective, but brutal. Switch it off and the handling is less lairy than you might expect, but on a wet road you need a surgeon's delicacy.
Our C version was equipped with 265/35/19 front tyres and 305/30/20 rears. It also had AMG's Dynamic Plus package of dynamic engine and transmission mountings, firmer, specially-tuned suspension and a Race mode setting costing £1,795. It also gets AMG's rear-steering system, which is also on the R version, which rams the rear wheels against their suspension bushes, turning them in and out by 1.5 degrees to aid agility. That's in the same direction as the front wheels at above 60mph, which makes the car feel longer and more stable, and in the opposite direction at low speeds, which makes the car feel shorter and easier to manoeuvre. All the cars came with £5,995 carbon-ceramic brakes, a mysteriously named 'mirror package', and £1,495 adjustable damping. Relax, I've only spent £156,230 of your pension here...
The GT is built around an aluminium and magnesium spaceframe consisting of extrusions welded into castings for strength and lightness - those long doors could double duty closing a bank vault.
At low speeds, the C, with its harder springing on all-double wishbone suspension, feels so stiff your shoulders jiggle in their sockets. Expansion joints, over banded roads and sharp-edged holes sound like a fight in the TV version of Batman; Blam, Pow, Kerbang! Coupled with those hard seats, the ride is uncomfortable and borderline harsh.
The same car's electronic variable steering feels accurate and well weighted but a bit darty when you are driving fast. It lacks feedback, however, and there's a small dead period around the centre. The biggest issue, however, is that it doesn't inspire much confidence. Despite the phenomenal level of grip generated by the tyres, you simply don't know what's going to happen when you turn this powerful car into a corner, it's as if your primary means of communication with the chassis is flickering like a dodgy mobile phone signal.
While AMG has come to symbolise the more-is-more philosophy, in almost every aspect the less-powerful and cheaper GT Roadster felt a better road car. Whether that was its more mannered power delivery, its narrower tyres or the softer rear suspension, I'm not sure, but these small differences added up to a lot. The standard car rode better on Phoenix's long boulevards, 'breathed' more easily over bumps, communicated more fluently with the driver and as a result felt more wieldy and more fun.
Not that UK buyers will value this quite as highly; swank power is just as important. GT coupé sales are only a couple of hundred a year and the more expensive and faster S version is the better seller.
I questioned why we had to travel all the way to America to drive this new German-built Merc, but it became clear as soon as I pressed the starter. The GT Roadster is a deliciously old-fashioned idea; a big front-engined gran turismo, an American muscle car, with all the charisma and drawbacks that entails, but pretty hard not to love. Just don't get carried away with your wallet and remember that even with AMG, less is often so much more.
Mercedes-Benz AMG GT C Roadster
TESTED 3,982cc twin-turbo V8, seven-speed automatic gearbox, rear-wheel drive
PRICE/ON SALE £110,145 for GT Roadster, £139,445 for GT C Roadster/summer
POWER/TORQUE 549bhp @ 5,750rpm, 502lb ft @ 1,900rpm
TOP SPEED 196mph
ACCELERATION 0-62mph in 3.7sec
FUEL ECONOMY 24.8mpg/18.7mpg (EU Combined/Urban), on test 25.8mpg
CO2 EMISSIONS 259g/km
VED £2,000 first year, £450 next 5 years, then £140
VERDICT Despite pretensions of high-tech performance, the GT Roadster is a deliciously unreconstructed muscle car, where ride and comfort take a back seat to all-out performance. Don't get carried away with muscle for this muscle car, however; the lower-powered standard car is better balanced and a nicer drive.
TELEGRAPH RATING Four stars out of five
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