I know it's not in BMW's plans for the current generation M2 (
Autocar reported that there will be a next generation M2), but...
IMO, it would be easy to increase the wheelbase of the current M2 to make a Gran Coupe. BMW has done a long wheelbase 3 series version for the China market (which 3 series GT platform)...
Below renders with animated gif to show the difference...
The elongated body makes the car look more elegant IMO.
