As a beginner or even intermediate musician, you do not hop up on stage with jazz legend Dizzy Gillespie (were he still alive). If you’re not confident in your ability to keep up with all the chord changes, where you are in the song’s form, or the sheer tempo blowing by like a runaway train, it becomes a disaster. But overcoming intimidation and stretching one’s self is part of musical growth. The Mercedes-AMG GT R is the automotive Dizzy Gillespie and taking the wheel is the equivalent of sitting in with him. The timid will run away. But then they’d never know how easy it could actually be to sit in with the jazz master.

With aggressive spoilers, a gaping and hungry toothed grille, huge tires and a pounding V8 engine, the AMG GT R glowers as you approach it, much like an imposing Gillespie might at an open jam session… until the music starts. If the GT R could bark or snarl, it would do that, too. Turns out, though, that the big attitude is largely show.

The AMG GT R does not start life as a normal GT or GT S model with additional boost shoveled on top. And you would be a certifiable lunatic to approach anything even half-way near its limits on public roads.

Lightweight components, if not a lightweight car

Lightweight components abound on and in the GT R. The roof, front splitter, front fenders, rear wing, rear diffuser, several braces under the car, and the torque tube tying the engine and transaxle together are all carbon fiber. The front carbon-ceramic brake rotors measure 15.8 inches in diameter (401mm) and use six-piston calipers.

By the way, the carbon-fiber front fenders allow a wider front-track width by 1.8 inches (46mm) while the rear track jumps by 2.3 inches (58mm) over the non-GT R. This nets additional room for fitting larger 19×10- and 20×12-inch-wide forged alloy wheels wrapped in Michelin Pilot Sport Cup 2 tires—street-legal track tires if ever any existed.

Truth be told, the GT R is a very rough sports car to live with solely on the street. It was born for the track. The smallest grooves and ruts in the highway turn the GT R into a bloodhound hunting a scent, juking from side to side. When cold, the carbon-ceramic brakes feel distant and touchy. Normal-sized bumps turn into kidney punches. Driving the GT R like a normal SUV or sedan turns you into a boxer’s sparring partner.

But then you arrive at the track. In this case, the Bob Bondurant Racing School’s West Track.

On-the-road-terror becomes a track-bound pussycat

Holy hell. I’ve run the essentially race-prepped Bondurant School Dodge Vipers around this place before (though the 600hp darlings were officially retired last year). The GT R is at least as quick, despite being about 300 pounds (136kg) heavier. But the GT R’s outright quickness around the course is not the biggest takeaway; it’s how easy the car is to drive at that pace. With a hood that long, with that much weight, with that much polar moment (the transmission being situated in the back and the engine towards the front-middle), you might think it’d be a pig dynamically.

Just the opposite. The engine itself is more closely mid-mounted than some cars with the engine actually behind the occupants; the 4.0L twin-turbo V8 is completely behind the front axle line and half-under the dashboard. Porsche is long-credited with making a dynamic silk purse out of a sow’s ear with the rear-engine 911 and with good reason: that set-up overcomes physics. But the same is almost as true for the GT R.

The old AMG stereotype is that of a German musclecar with way more engine than chassis. If that was ever true, it no longer is, but the fact does remain that engines are the company’s biggest jam. Compared to the standard-issue AMG GT, the cylinder heads’ ports are honed and enlarged slightly to improve flow, and the two BorgWarner turbochargers grow in size, too.

The standard AMG GT engine is no slouch, but the GT R bests the GT S by 74 horsepower (55kW) and 37lb-ft (50Nm), barking out 577hp (430kW) and 516lb-ft (700Nm) of torque. The increase is largely due to greater boost at 19.6 psi (1.35bar) from 17.4 psi (1.2 bar), but that also mandates a drop in static compression from 10.5:1 in the GT to 9.5:1 for the GT R.

Mercedes-AMG uses the same seven-speed dual-clutch transmission from the GT and GT S models, but ratios are juggled a bit to get the spread from 1st through 7th a bit closer. Since it’s actually a transaxle, it incorporates an electronically controlled limited-slip differential.

The GT R actually flies a multifaceted flag on track. There’s a bevy of tweaks you can select from the driver’s seat in order to dial things in to your liking. Chassis, engine, and transmission responsiveness come in five attitudes: Comfort, Sport, Sport Plus, Race, and Individual (for which you tweak each individual parameter yourself). Dampers themselves have two different settings as does the exhaust. You can also specify manual gearchanges.

Once acclimated and up to temperature, front grip doesn’t quit until you ask something really stupid of it, and at that point, it quickly tells you you’re being stupid and to precisely what level of stupidity. And with an adjustable stability control knob straight in the middle of the dash where you can dial in the level and threshold of intervention, you can be an instant hero. If you try left-foot braking as done in single-seat race cars (or racing karts) where there’s inevitably overlap in pedal application, the GT R can actually cope. The powertrain and stability calibration allows you to seek top outright speed, as long as you’ve chosen the right stability setting. You can pick up the throttle on corner exits before completely releasing the brake, which is unlike nearly any production car I’ve driven.

But the notion of a driver tuning his own level of stability control—even within various modes—is pretty astonishing. A dash-mounted nine-position knob allows an increasing level of slip as you dial it clockwise. And this feature is only on the GT R, not the GT or GT S.

Taking variability even further, adjustable-perch coil-over spring/damper units allow ride-height changes and pre-loading of springs, just like a real race car.

The incredible shrinking supercar

Back out on track at Bondurant, the 109°F degree (43°C) day would normally spell doom for the brakes on a 3,500lb (1,588kg) sports car. Not for the GT R. Not only did the brakes happily gobble up all the heat of a 15-minute session in brutal desert conditions, so did the engine and transmission. The highest speed encountered on this particular course in the GT R was about 145mph (233km/h), which reduces down to a flat, 60mph or so left (97km/h). This means repeated hard braking for a significant duration, lap after lap. Not to mention the other eight heavy braking zones. No sweat for the GT R’s brakes.

The GT R also turns in far more responsively than any 3,500-pound car has a right to, and that’s not just down to the car’s steering (at both ends, as the car has four-wheel-steering). The electronically controlled differential can assist yaw under braking, too. Dynamically, the car simply shrinks in size and mass on track, unless you start sliding around intentionally. However, the rearward seating position relative to the car’s centerline heightens the sensation of oversteer when hooning like a drift king.

It all adds up to a top-shelf, $160,000 (at minimum) track-day special in the Porsche 911 GT3 RS and Corvette ZR1 camp. And though the GT R is large and heavy, those traits diminish the faster you run it.

Listing image by Jim Resnick

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