BMW has been hard at work lately testing the next generation M4 Coupe. The newly redesigned coupe and its M3 sedan brother are due for an unveil by the end of this month. Naturally, prototypes are now being seen all over the world putting the final testing miles on the odometer.

One of those prototypes kept popping up on our radar. Initially, we believed that BMW is testing their future M4 CSL – which they might in the end – but the rumor is that this particular test mule is a regular G82 M4 with some new M Performance Parts. And this is where things get interesting.

Not only that the M4 prototype was featured with a cool looking rear spoiler, it also sports a quite unique exhaust system. One interesting note about this alleged M Performance exhaust is that the new arrangement is surprisingly different from the standard car’s.

With the quad exhaust tips moved from the outer sides of the rear bumper to the center, in a sort of stacked pattern, the new exhaust system would actually require a different diffuser to accommodate them. Additionally, it could also require entirely different exhaust hangers underneath. So it’s likely going to be an expensive option.

Related: SPIED: BMW M4 Convertible Seen Testing with Roof Up

The good news is that BMW M is working on these parts now, so customers don’t have to wait until after taking delivery to get the parts fitted to their cars. One of the best aspects of buying M Performance upgrades over aftermarket ones is the ability to get them from the factory, already fitted to the car upon brand-new delivery, included in the monthly payment and the car’s original warranty.

So this brings us to the topic today. Our friend @zer.0.wt has decided to render the rear-end of the new M4 with these M Performance Parts. And the result, in our humble opinion, is stunning. The slim taillights and darkened accents play well with the aggressiveness of the spoiler, and especially with the diffuser and new exhaust.

The car looks extremely sporty, with a great stance and quite unique on the road. Whether that exhaust system ends up in the M Performance Parts catalog, remains to be seen. But knowing BMW M, we should have an answer as soon as the veil is lifted off the new M3 and M4 models.