While we are waiting for the new generation of the Mercedes-AMG GT to arrive, German company BSTC Performance has unveiled a tuned AMG GT R with a series of visual and mechanical upgrades. With a power output of 891 hp (664 kW / 903 PS), the tuned sportscar is more powerful than the flagship AMG GT Black Series, leaving many modern supercars behind.

BSTC Performance is specializing in used Mercedes parts, thus they upgraded the GT R with original components from the GT R Pro and the facelifted GT range. These include the new LED headlights and taillights, the redesigned front bumper with carbon-fiber canards, sportier side sills, the rear bumper with vents and a carbon fiber diffuser expanding towards the sides, and a fixed rear wing. The AMG Performance forged rims are also from the AMG GT R Pro, shod in Michelin Pilot Sport Cup 2 tires measuring 285/30R19 up front and 335/25R20 at the rear.

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The twin-turbo 4.0-litre V8 engine has been upgraded with a new pair of turbochargers from Weistec Engineering, air coolers from Wagner, IPE downpipes with 200-cell sport catalytic converters, an ARMA carbon-fiber intake, and tweaked ECU software in order to unlock its full potential.

As a result, the power output has been increased from the stock 577 hp (430 kW / 585 PS) to 891 hp (664 kW / 903 PS), making it more powerful than any OEM variant of the AMG GT, including the Black Series which makes 720 hp (537 kW / 730 PS). Power is sent to the rear axle through the AMG Speedshift seven-speed dual-clutch transmission that has been upgraded to cope with the increased power.

BSTC didn’t reveal the performance credentials of the tuned AMG GT, but we suspect it will be a tad slower around the track compared to the Black Series which comes with a more focused chassis setup and a more aggressive aero bodykit. Having said that, with that much power on tap, we guess that, on a straight line, the tuned GT should be faster.