I like the agressiveness of the C63 over the M3 4 door. It looks too much like a plain 3 with an M3 nose. Driving experience wise, I'd most likely take the M3 even though the big motor and its torque would be nice.

However, if I were to go that route after the 550i, it would be the M3 coupe. I think it looks great. More agressive than the sedan but not enough to be "ricey".

 

Now that the price is out for the M3... heck All hail M3.