With just over 500 horsepower and 479 pound-feet of torque at its disposal, the Mercedes-AMG GT S is far from what you or I would consider a supercar. It’s got some burn to it, sure, but it’s not going to win any races when you line it up against the Lamborghinis and Ferraris of the world. Imagine, then, what kind of program it would take for the AMG GT S to have the muscle for that action. Well, stop imagining because it’s actually come to life, all thanks to the fantastic folks over at IMSA. For your enjoyment, folks, I present to you the Mercedes-AMG RXR One Super Gran Turismo by IMSA.

Now, this is what a fully realized AMG GT S is supposed to look like. It may not be as sexy as its big bro, the AMG GT R, but it sure does make up for it in extra girth and muscle. That transformation was achieved in large part because of the work put in by the German tuner. There’s plenty to discuss here, including the steps by which IMSA was able to not only visually transform the AMG GT S. but increase power and performance to reach certified supercar territory.

Continue after the jump to read more about the Mercedes-AMG RXR One Super Gran Turismo

Exterior

Carbon fiber, carbon fiber, and more carbon fiber. That was the blueprint IMSA laid out in designing the exterior upgrades for the AMG GT S and it followed it to a tee. What you see here now is a sports car dripping in the precious (and lightweight) stuff, including on the whole bumper and spoiler assembly, hood, roof, wings, trunk lid, and, of course, the rear wing. Take out the whole panels and put these carbon fiber pieces on the car, and you’re looking at a coupe that, at least according to IMSA, now weighs just under 1,300 kilos (2,866 pounds). Do the math and that’s weight savings amounting to 300 kilos (661 pounds). It may not sound like much, but it’s a huge diet for a car that relies heavily on its performance credentials.

Finishing off the exterior upgrades is a set of 20- and 21-inch lightweight forged alloy wheels from IMSA Racing. These wheels are then wrapped in 305/30-series and 315/30-series Pirelli P Zero Trofeo R tires in the front and rear, respectively.

Interior

Note: Standard Mercedes-AMG GT pictured here.

There’s always a rub when it comes to interior upgrades. Some tuners proudly showcase theirs whereas some ignore this section of the car completely. Then there are those that offer personalized upgrades, which essentially leaves it in the customer’s hands. IMSA’s interior upgrades for the AMG GT S sit along those lines, other than the fact that the tuner installed a roll cage inside for safety reasons. Apart from that piece of equipment, every surface that can be improved upon in the cabin lies in the personal whims and preferences of the buyer. That’s why IMSA refused to identify what kind of upgrades it gave to this showpiece model since the absence of expectations make it far more interesting for potential buyers of the whole program.

Drivetrain

Programs or projects with insanely long names are usually indications that a specific kit has something special to offer. The Mercedes-AMG RXR One Super Gran Turismo is no exception because its engine upgrade is, in a word, potent. It also involved a lot of work on IMSA’s part, including the modification of the sports car’s turbochargers, the addition of new forged pistons, the installation of a new intake and intercooler, and the complete re-engineering of all these new components that allows them to function and live up to the enormous expectations IMSA put on its shoulders.

Happy to say, then, that the result more than lived up to the hype. The Mercedes-AMG RXR One Super Gran Turismo now has 848 horsepower and 738 pound-feet of torque at its disposal. Plain and simple, those are supercar-worthy numbers. Much more important are the ramifications of having that much power at the sports car’s disposal. IMSA didn’t say how this massive engine spike translates as far as performance times go, but let’s go back to the part of the car weighing 300 kilos less than its standard counterpart. If the AMG GT S can hit 0 to 60 mph in just under four seconds, the AMG RXR One Super Gran Trusmo should have enough (extra) power in its engine to blow that figure out fo the water.

Don’t be surprised if the difference is massive either because, in my mind, the AMG RXR One Super Gran Turismo should be able to cover the same ground in the low-three-second mark. Perhaps somewhere in the vicinity of 3.1 to 3.3 seconds and a top speed in excess of 217 mph? Those numbers are completely unattainable for a standard AMG GT S, but they should be well within reach for a heavily modified AM GT S like the AMG RXR One Super Gran Turismo.

Suspension

No surprises on this front either, considering the kind of power the AMG RXR One Super Gran Turismo has at its disposal. Somebody puts that many upgrades on a car and it’s bound to need suspension upgrades to help the sports car maintain an appropriate amount of balance and sufficient handling. So, that’s precisely what IMSA did, and it threw in carbon ceramic brakes behind the wheels for good measure.

Price

Did you expect a specific price figure for this program? If you did, then I’m sorry to disappoint you because IMSA isn’t releasing any pricing details. That’s probably due to the fact that there are elements in the whole program - the personalized options - that would cause the final price to vary. The tuner did say that it’s only building a limited number of the RXR One Super Gran Turismo, so if you’re interested in getting one, now’s as good a time as any to make that inquiry. Who knows, if you hold off on doing it, you might lose out on the however many models IMSA plans to build.

Competition

Mercedes-AMG GT S by Lorinser

It’s been a while since the Mercedes-AMG GT S received a significant tuning upgrade that made a lot of noise in the business. There have been some past kits that have piqued our interest over the years, including this one from Lorinser. It’s actually one of the first programs were featured for the AMG GT S and it certainly didn’t disappoint, though it probably would’ve been much better if it featured an aero kit of some sort.

In case, the program did have a hefty engine upgrade amounting to an increased output of 595 horsepower and 516 pound-feet of torque. Consider that the AMG GT S came with a standard output of 503 ponies and 479 pound-feet of twist and you’re looking at extra power amounting to 92 horses and 37 pound-feet of torque. According to Lorinser, the upgrades are good enough to help the sports car hit 0 to 62 mph in just 3.6 seconds. A 0-to-124-mph time has also been clocked at 10.1 seconds on its way to hitting a top speed of 186 mph.

Read our full review on the 2016 Mercedes-AMG GT S by Lorinser.

Mercedes-AMG GT S by Mansory

If there ever was a tuning kit that really put the fear of metal on the AMG GT S, it was Mansory’s program from the 2016 Geneva Motor Show. This one covered the full boat, beginning with a massive carbon fiber wide-body kit made up of components like a front lip spoiler, a ventilated carbon fiber hood, wheel arch extensions, extended side skirts, and a fancy rear wing at the back. Those pieces were complemented by a fancy work on the interior that included red carbon fiber sports seats dressed in a hand-stitched, three-color premium leather upholstery.

The real highlight though is the work Mansory put into the sports car’s 4.0-liter Biturbo V-8 engine, none more important than replacing the existing turbochargers with larger turbos and installing a high-flow air filter and adding an optimized ECU unit. The result is an output of 730 horses, a massive bump of 227 ponies over the standard AMG GT S, and translating itself to an acceleration time of just 3.4 seconds from 0 to 62 mph to go along with a top speed of 205 mph.

Read our full review on the 2016 Mercedes-AMG GT S by Mansory.

Conclusion

Without question, this is one of the most comprehensive tuning programs that I’ve seen created for the Mercedes-AMG GT S. There have been a lot of them, sure, but very few have come within the scope of what IMSA was able to do. From the generous use of carbon fiber on the aero kit to the personalized interior options and the robust engine upgrade, the German tuner left no stone unturned in turning the AMG GT S into a full-fledged supercar with ill intent on anybody that gets in its way.

References

Mercedes-AMG GT

Read our full review on the 2017 Mercedes-AMG GT.

Read more car tuning news.