With the new generation M4 Coupe scheduled to make its official entry towards the end of September, BMW M appears to have started working on a more track-focused version.

An image has been circulating on the web this week, showing a tester with a stacked center tailpipe layout and a fixed rear wing, and now the same prototype has been spotted again, parked next to the standard M4.

Related: BMW M4 Convertible Spied With Less Camouflage, Will Have Up To 503 HP

So, what is new? There’s that big fixed rear wing, for one, but the eye-catcher is no doubt the exhausts. Flanked by subtle fins added to the rear bumper, the diffuser is also new and incorporates the central-mounted quad exhaust pipes. A more prominent apron has been added to the front bumper, and while it is hard to tell from these angles, the front wheel arches seem to be a bit wider.

Until further proof, we cannot say for sure whether this is the next M4 GTS, but assuming it is, then expect a host of other technical improvements too over the M4 Coupe. These will include a revised chassis, with a firmer suspension set-up, beefier brakes and possibly minor weight improvements.

The twin-turbocharged 3.0-liter straight-six engine should be tweaked to deliver more horses than in the base and Competition versions of the M4, where it produces 473 HP (480 PS / 353 kW) and 503 HP (510 PS / 375 kW) respectively.

It will be interesting to see whether the rumored M4 GTS, which could be due late next year, will get the M-tuned xDrive all-wheel drive system or if it will be offered with rear-wheel drive setup only, and if the engineers opt for the six-speed manual or eight-speed automatic transmission.

Photo Credits: @audikind for CarPix | CarScoops