It goes without saying that a sports car with any hope of going head-to-head with the Porsche 911 has to be available in both coupe and convertible variants — not to mention about a bazillion derivatives.
Engine: 4.0L twin-turbo V8
Output: 469 hp, 465 lb-ft; 550 hp, 502 lb-ft
Transmission: 7-speed dual-clutch auto
0-60 mph: 3.9 seconds; 3.6 seconds
0-100 km/h: 4.0 seconds; 3.7 seconds
US Fuel Economy (MPG): Unavailable
CAN Fuel Economy (L/100 km): Unavailable
US Price: Starts at $124,400
CAN Price: Starts at $145,000 (est.)
Despite what some folks from the Mercedes-Benz mothership might say, that prerequisite for hunting Porsches is exactly why the market will soon be blessed with the 2018 Mercedes-AMG GT Roadster. It’s part of a natural progression that will see the stable of SLS successors soon swell to six, including not one but two high-horsepower convertible models hell-bent on blistering levels of speed and sun exposure.
Two Ways to go Topless
Choosing between the two GT Roadsters is a bit like deciding between a T-bone steak and a porterhouse: Both deliver plenty of flavor, though the porterhouse has a little more meat on the bone. In this case, think of the base droptop as the T-bone. Pricing starts at $124,400 in the U.S. (estimated at $145,000 in Canada), and output from the twin-turbocharged 4.0-liter V8 nestled between the front fenders is rated at a very respectable 469 horsepower and 465 lb-ft of torque.
That power heads to the rear wheels through a seven-speed dual-clutch automatic transmission that’s mounted between the rear wheels to improve balance and weight distribution. The limited-slip differential is a mechanical one, while the suspension setup isn’t adaptive but does feature double wishbones at all four corners.
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Step up to the Mercedes-AMG GT C Roadster and its $157,000 price tag (estimated at $180,000 in Canada), meanwhile, and the result is more than an output increase — though that alone is significant. Modifications to the car’s engine tuning push output to 550 hp and 502 lb-ft of torque, necessitating the addition of an electronically controlled limited-slip differential.
The list of changes only grows from there. Borrowed from the AMG GT R coupe, a rear-wheel steering setup is along for the ride, while the rear wheels and tires measure more than an inch (25 millimeters) wider each, and are hidden beneath wider rear fenders. It also gets larger front brakes — they measure 15.4 inches compared to 14.2 inches in base trim — while the drive mode selector adds a Race position for even more aggressive throttle mapping and transmission programming.
Structural Integrity Intact
Of course, chopping the top off of a high-powered coupe and calling it a day is often done at the peril of the spirit the car must maintain. Removing a car’s roof means reducing torsional rigidity. Sapping that stiffness affects its ability to corner properly, which is particularly detrimental to a sports car.
To make up for what was lost in its conversion from coupe to convertible, the Mercedes-AMG GT Roadster was fitted with all sorts of reinforcements and additional bracing. The rocker panels are thicker, for example, while a handful of struts and supports were added beneath the sheet metal. The result is no noticeable loss in torsional stiffness compared to the coupe. The GT Roadster is the same battle axe that was forged in fire — albeit with a slightly different shape.
While it’s fundamentally the same as the coupe that was introduced almost three years ago, the Mercedes-AMG GT Roadster has a look that’s all its own. That’s particularly the case for the GT C, which features a lot of bulging body panels and has serious shades of the SLS that came before it.
Driving Through the Desert
But don’t let the ‘GT’ name fool you: This is no grand touring automobile. Instead, it’s a purpose-built weapon that’s really good at driving really fast — and in more than just a straight line. And it’s for that reason that this isn’t a car for everyone.
Heading out from the heart of posh Paradise Valley, Ariz., behind the wheel of a matte grey AMG GT C, the car was more than willing to play nice in Comfort mode. The adaptive suspension was left in its softest setting as we headed north and then west towards more sparsely populated land. The hot sun was beating down hard in the early morning hours and so the top was left up, where the cabin proved to be quiet and cozy without reducing visibility too much.
Cutting back towards Prescott, almost a straight shot north of Phoenix, the ribbon of road ahead began to curl into tight turns and switchbacks. And it was there, with the top retracted, that the car felt most at home. It was also on those winding roads it became clear that, much like the coupe, this new GT Roadster takes a bit of skill to harness its full potential and use it productively.
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That’s not to say the car isn’t user friendly, because it is, but it’s not as forgiving as others in the AMG lineup. Even with the GT C’s rear-wheel steering setup, which works wonders to shrink the roadster without interfering with its fun-factor, it can call for an added dose of determination to negotiate a corner at speed.
Likewise, corner exits must be handled with care, as generous throttle inputs can force the rear end to step out, however slightly, at a moment’s notice. It is, however, easy to anticipate most of what the car is going to do. The stiff chassis and suspension are incredibly communicative, while the steering is crisp and offers plenty of turn-in response. It’s certainly not as mechanical as something like the Alfa Romeo 4C, but the steering setup is an impressive one considering it’s connected by wires. With the transmission set to manual mode, flicking the paddle shifters is rewarded with incredibly quick gear changes that leave the car primed to rocket through corners thanks to the active rev-matching.
This AMG-tuned 4.0-liter engine keeps its turbos nestled between its cylinder banks, something the brand says helps reduce turbo lag and pressure loss. There’s no reason to dispute that claim. Throttle response is tack-sharp and tactile, sending the car around like a rocket ship when pedal is pressed.
It also happens to sound great, too — especially with the sport exhaust system along for the ride. And that’s one inherent advantage this GT Roadster brings with it compared to its hardtop sibling: Its soundtrack. While the coupe sounds equally excellent, the exhaust note is somewhat muted inside, leaving most of the enjoyment to those within earshot. But not here. Fold the top back and every octave of the exhaust reverberates in the cabin in the best way possible.
It’s a surprisingly visceral experience that’s neither too overbearing nor too unrefined. Any one of the umpteen Porsche 911 models on the market is great, but it feels far more surgical and precise. In the AMG GT Roadster there is still the need to wrestle it around to maximize its full potential, and the experience is better for it. And best of all, the roadster feels every bit as dynamic and agile as the coupe, with nothing lost in translation.
A Look Inside
For better or for worse, the car’s cabin belies that performance prowess. Like the coupe, it looks and feels every bit as exotic as any of its peers while featuring a few more track-ready characteristics.
Get past the dainty little shift lever and the center console looks like an anthill of inlaid buttons and knobs aimed to excite. Everything from the glowing red engine-start button to the active exhaust and drive mode selector are easily within reach of the driver and ready to deliver sensory overload when the mood strikes.
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Equally — though almost unfortunately — geared towards the sporty end of the spectrum are the seats. They can be adjusted 12 ways to Sunday but are stiffer than perhaps they need to be. It didn’t take long into our 320-mile (515-kilometer) journey through the desert to wish for something a little more comfortable. Unfortunately, there are no other options available on the North American market.
As a low-slung sports car, the GT Roadster poses some challenges getting into and out of. Despite the low position of the seats, the tri-layered top can lead to some feelings of claustrophobia for drivers taller than, say, 6-foot-3. But the reason to buy the roadster in the first place is driving with the top down, and doing so is a reward all in its own. Folding it only takes about 11 seconds and can be done at speeds as fast as 31 mph (50 km/h), opening up the cabin to all the benefits of an open-air roadster without much buffeting or bother from the wind.
The Verdict: 2018 Mercedes-AMG GT Roadster Review
Let the folks in Affalterbach loose with a Sawzall and this is what they come up with: A stunningly beautiful, Porsche-hunting roadster that sacrifices very little compared to its coupe counterpart. In short, it’s a hot rod with a haircut. Any fears that this convertible version would lose the raucous and raw attitude of the GT coupe should be thrown right out the window. On second thought, make it the open top.