Having driven the Mercedes-AMG GT R I can confidently say that it is in no need of a power boost but German tuning shop known as RENNtech think otherwise.

From the factory the track-honed ‘Beast of The Green Hell’ is gifted with 577 hp (430 kW) but with the upgrade package from RENNtech, your range-topping AMG GT can deliver anything from 612 to 825 hp (456 to 615 kW), depending on your configuration.

The 825 horsepower (615 kw) option has been dubbed the AMG GT R825 for obvious reasons and this tune also means the 4.0-litre biturbo V8 turns out a whopping 850 Nm of torque.

All that extra power comes courtesy of larger turbo, paired with a software upgrade, blow-off valves, and high-flow air filter, among others. Both the transmission and clutch have been reinforced to cope, of course.

Externally RENNtech add some modest touches including a unique aero package, which was first shown at the Top Marques Monaco earlier in the year. The new look includes an aggressive front bumper with canards, sharper side splitters, and a special two-stage rear wing.

The full package also includes a set of lightweight forged Vossen wheels, wrapped in some sticky Michelin Pilot Sport Cup 2 ZP tyres.

No word on pricing but you can bet the full 825 hp upgrade will sting the wallet properly.