This rendering by (Jon Sibal?) gives a very good indication of how the car is progressing. This shape is is very much similar to the outline of the car and how it fits within the 3er portfolio. If you focus on the outline and not the detail you can see how the car can carry the M3 badge. Think of the CS Concept shrunk down for the premium entry segment and you get the BMW 3er Gran Turismo.
It is known as Progressive Sports Coupe.