Renntech boosts the Merc-AMG E63 S to 809bhp

German tuner Renntech has devised a faster, more powerful iteration of the already-hugely-fast, already-hugely-powerful Mercedes-AMG E63 and E63 S. It is called the R800.

We haven’t got time to go into the ‘why’, but instead shall focus on the ‘what’. A software tweak to the 4.0-litre turbo V8 and gearbox liberates up to 789bhp and torque limited – limited – to 774lb ft.

Seven hundred and eighty-nine horsepower. Note that a regular, showroom-fresh E63 S churns out 604bhp, while a ‘standard’ E63 produces 567bhp. Both of those latter factory figures are indeed plenty of horsepower for your average, super-saloon buying human.

So you want more, naturally. Tick the option for Renntech’s special exhaust system with ceramic coated downpipes and 200-cell sports cats, and you’re looking at the very thick, likely very scary end of 809bhp.

Noise… could be an issue. Renntech assures us that this new exhaust system generates “a phenomenal sound”, at least if you’re in the ‘Sport’ or ‘Sport +’ modes. ‘Comfort’ mode with this barking new exhaust apparently nearly matches the same level of noise as the regular car. Your neighbours will be delighted.

Futhermore, in the full nutjob 809bhp configuration, this Renntech E63 S is capable of hitting 133mph in just 10.43s.

A cursory scan through the images showcases Renntech’s minor upgrades for the interior and exterior, too. A fine environment in which you vainly attempt to keep the 809bhp R800 pointing in a straight line...