It's no secret that BMW is preparing a hardcore M2, potentially to be called the M2 CS, and it could debut as early as September at the Frankfurt Motor Show. We've seen it testing once before at the Nurburgring, and at the time we figured it'd be fitted with a detuned version of the M3/M4's 3.0-liter turbocharged straight-six engine. And now we know pretty much for sure BMW has opted for this engine. Automotive Mike just recently filmed an M2 CS prototype back at the Nurburgring and the sound it makes is nearly identical to that of the M3/M4.

It's much throatier than the M2's acoustics. The car itself, though hidden in the usual camo, does feature new headlights, taillights, and grille. It will look unique compared to the M2. And because of the sheer amount of power going to the wheels, the M2 CS will feature much larger steel brakes (carbon ceramics will probably be an option).

And M3 exhaust is also likely. With the M3 Competition Package, this engine produces 444 hp but it'll be slightly less powerful in the M2 CS, figure around 400 hp. That's still a significant upgrade from the M2's 365 hp. Other modifications will include various suspension tweaks and additional aerodynamic parts, specifically a new front bumper, front splitter and rear wing. BMW seems to be getting the M2 CS ready for battle against the Porsche Cayman GT4, and that's one head-to-head we can't wait to see.