How is this widebody Mercedes-AMG GT still road legal?

German tuners getting hold of already tasty German cars is a rich seam of super-unleaded lunacy, and signs are it’s going to get even more out of hand before the world calls time on the internal combustion engine. 

Exhibit A: today’s latest offering, fresh from der Lower Rhine, from IMSA GmbH. This subtle vehicle was once a regular Mercedes-AMG GT S, developing 515bhp and 479lb ft. The standard GT S is a lively bit of kit, and not a car that wants for more power, unless it’s an upgraded GT C and GT R, which also plumb in rear-wheel steering and wider tracks to semi-tame the waywardness.

Clearly, IMSA’s elegantly titled ‘RXR One Super Gran Turismo’ does not want for, er, girth. The monumental sills, pumped-out arches and massively enlarged vents signal a great amount of intent and fury. And well they might, given the 4.0-litre bi-turbo V8’s allegedly been boosted to 848bhp. Oh, and 738lb ft.

This enormous power rush comes courtesy of forged pistons, an uprated intercooler and intake, and new turbos. It’s supposed to be tamed by 315-section rear tyres, and even the undriven front tyres have been stretched to 305mm across. We’re not sure how successful the quest for traction has been, because IMSA has neglected to make any 0-62mph or 0-100mph claims. 

All of that flared bodywork is carbonfibre, as is a rear wing so enormous we’re fairly sure there’s a GT3 racing team currently double-checking its spares manifest looking for an extra spoiler. As a result, the RXR One Super GT is light -  under 1300kg light, in fact. If accurate, that makes this thing's about 300kg lighter than the standard car, and over 300bhp more powerful. Flipping heck. No wonder you get a roll cage.

Thing is, with such bonkers aero, a roll cage, massive tyres on centrelock wheels and a vicious diet, this is far more 'racing car' than it is 'road car'. Yet, instead of being restricted like the GT3 version, the engine’s got a whole Golf R’s worth of extra poke. How on Earth the RXR is allowed to be driven on the road is anyone’s guess. Question is, would you want to?

Oh, and is anyone else disturbed by how pathetically tiny the exhaust pipes are, given the power and general outrageousness elsewhere? Talk about an afterthought.