It’s not hard to get excited by a Mercedes-AMG sports car aimed at the Porsche 911. But it can be hard to wrap your head around the Mercedes-AMG GT lineup. First there was the GT S, which was followed by an entry-level, non-S GT. Then came the other bookend, the top-of-the-line GT R, and the race car, which gets no name at all beyond the class it sometimes competes in: Mercedes-AMG GT3. Then came the inevitable GT convertible, the GT C, which seemed to be positioned as the roadster complement to the GT S coupe—until it was announced that there will be a GT C coupe as well. Naturally, there’s also a non-C convertible. There’s no word on an R convertible, although there will be a four-door model from AMG badged as a GT that almost certainly will be available in many, if not all, of the aforementioned trim levels. (When discussing these options with your spouse or financial manager, keep in mind that there are GT S and C coupes and convertibles, but Mercedes also makes S- and C-class coupes and convertibles, which cover a wide price range. Employ specifics and vagaries as necessary to obtain a blessing for your desired derivative.)
As confusing as all this can seem, it’s what you do when chasing the 911: You slice your pie thin and add so many layers, spinoffs, and special editions—the GT C’s first has already been announced—that it starts to resemble a pie five minutes after it was served to an unsupervised toddler. Or a model of the solar system that accounts for at least three more dimensions than the average human is cognizant of. Or the frenzied pursuit of money, money, money, money.
At any rate, we now have driven two more slices/branches/wormholes of the space-time pie: the GT roadster and GT C roadster. Weight gain compared with the coupes is minimal, just 110 or so pounds in the GT and only about 75 pounds in the C, according to Mercedes. A trunklid of carbon-fiber composite offsets some of the gain. The roadsters get additional bracing in the dashboard and the rear bulkhead, a rear tower brace, and reinforced sills. The result is a car that not once in our drive around central Arizona shuddered or otherwise reminded us it was a convertible, except when we realized our faces were assuming the texture of pork cracklins. Luckily, the top raises or lowers in just 11 seconds, at speeds up to 31 mph.
Hot Vee, Hot Stats
Both versions faithfully track their coupe siblings. For the GT, that means 469 horsepower and 465 lb-ft of torque from the twin-turbocharged 4.0-liter V-8 routed to a rear-mounted seven-speed dual-clutch automatic transaxle. For the GT C, the eight pumps out 81 more horses—550 in total—and 502 lb-ft of torque. The C borrows quite a few pieces from the lunatic GT R coupe, much of it concentrated in the back half of the car. The C shares with the R its wider rear fenders, rear-steering system, taller first and shorter seventh gears, taller final-drive ratio, and electronically controlled limited-slip differential. Both droptops borrow the grille shutters from the top dog’s front fascia and its dynamic engine and transmission mounts, which vary their stiffness, lessening it to isolate the occupants from the thrashing of the drivetrain’s mass or firming up to better control load transfer during aggressive driving.
Like the coupe, the AMG GT roadster is snug inside. Pop the hood and it’s easy to see why: The traditional AMG engine cover—signed by the engine builder, of course—is right there at the front of the bay. But on second glance, you realize that the cover isn’t actually concealing the engine. It covers the radiator and coolant-overflow tank, plus assorted hoses and ducting. The turbos poke up behind the cover, where the engine sits well aft of the front-axle centerline. Viewed as a whole, the actual engine and misplaced cover give the impression of a V-16 or something rather more exotic than a turbo V-8.
Not that the V-8 doesn’t generate plenty of excitement. The turbos dull its soundtrack somewhat, but the exhaust supplies plenty of pops on overrun, and the thrust is undeniable. Throttle mapping varies with the driving mode—Comfort, Sport, and Sport+, and a Race mode on the C—but even at its most relaxed, the engine’s response is immediate. Figure on the GT hitting 60 mph in just 3.2 or so seconds, with the C needing about 3.0 seconds. GT C drivers will appreciate that model’s simplified launch-control activation, whereby a traditional brake-torque approach—left foot on the brake, the right mashing the gas—frees the engine to rev to whatever speed the driver chooses using the shift paddles. Then just step out of the brake, the clutch dumps, and the car is gone.
Stuck Like Glue
That rearward positioning of the engine does wonders for the GT’s handling, which is simply stupefying. The GT is imperturbable, constantly goading its driver to enter corners faster, accelerate earlier and harder, and brake later. The stoppers are firm, progressive, and tireless. And the GT is daringly neutral, particularly with the C’s rear steering—which adds up to 1.5 degrees of toe either in phase with the front wheels above 62 mph or opposite them at lower speeds. A lighter lithium-ion battery and a magnesium radiator support (the latter also common to the base roadster) shift the C’s weight distribution rearward. Locating the occupants so far aft in the body amplifies the sensation of rotation, although neither car ever feels out of sorts. And while the GT C offers additional levels of damper firmness—and its most aggressive setting is notably stiffer than both its and the GT’s default mode—none is ever harsh. It is an effective apex duster and a comfortable tourer. You’d better pack light, however, as the trunk is fairly tight and there’s little interior storage. In terms of people space, the GT lands between the Jaguar F-type on the low end and the roomier 911.
Both versions of the GT roadster will be in U.S. dealers by this fall, but Mercedes has yet to announce pricing for either. Figure on the entry-level car starting around $135,000 and the C reaching into the $160Ks. At least in the financial sense, the hierarchy is clear.
VEHICLE TYPE: front-engine, rear-wheel-drive, 2-passenger, 2-door convertible
ESTIMATED BASE PRICE: GT, $135,000;
GT C, $165,000
ENGINE TYPE: twin-turbocharged and intercooled DOHC 32-valve 4.0-liter V-8, 469 or 550 hp, 465 or 502 lb-ft
TRANSMISSION: 7-speed dual-clutch automatic with manual shifting mode
Wheelbase: 103.5 in
Length: 178.9–179.2 in
Width: 76.3–79.0 in Height: 49.6 in
Curb weight (C/D est): 3800–3900 lb
PERFORMANCE (C/D EST):
Zero to 60 mph: 3.0–3.2 sec
Zero to 100 mph: 6.9–7.1 sec
Standing ¼-mile: 11.2–11.5 sec
Top speed: 188–196 mph
FUEL ECONOMY (C/D EST):
EPA combined/city/highway driving: 18/15–16/22 mpg