We haven’t even seen the “regular” G82 BMW M4 yet (it will be revealed very soon), and Munich is already building a hotter version of the sports coupé. These images, taken by Instagram user @audikind for our spy photographers at CarPix, show a development prototype with some serious aerodynamic addenda.

The M4’s flourishes are present and correct, of course – the controversial full-height kidney grille, larger front air intakes, bulging wheel arches, and twin-spar mirrors are all visible. But look underneath that grille, and you’ll find a splitter that gives this particular mule a harder appearance.

This aggressiveness continues along the side, with deeper skirts that flick up towards the rear of the car, visually meeting the also-extended rear bumper spats. But it’s at the back where the most significant changes are located – a sizeable rear wing and a redesigned rear diffuser, the latter containing some eye-catching stacked quad tailpipes clustered around the centre.

So, what could this car be? The most obvious guess would be a new generation of the track-focused GTS, judging by the extensive modifications – although it does seem a bit early in the M4’s lifecycle for that. The mule could also be testing out some M Performance parts, but last I checked, those components never included such a reconfiguration of the exhaust pipe layout.

Last but not least, this could be a prototype of the next MotoGP safety car. Munich has a track record of building bespoke pace cars for different race series, adding a massive GT-spec wing to its M8 for last year’s MotoGP season and even chopping the windscreen off an i8 for Formula E.

Whatever it is, expect the car to feature an uprated version of the standard M4’s S58 3.0 litre twin-turbocharged straight-six, which will produce 510 PS and 650 Nm in the most potent Competition variant. It should also get that car’s performance-oriented all-wheel-drive system and eight-speed automatic gearbox.

GALLERY: Camouflaged G80 BMW M4