I have not driven (or seen) the coupe. And the M3 is one of my favorite V8s money can buy. But I gotta tell ya...I drove a C63 Sedan with Performance Package last year (white on white), and the engine is EPIC. I know that word gets overused....but in this case it fits. Just HUGE torque everywhere, anytime. Massive torque, actually. If I was spending days at the track (or if I could wind the engine out all the time!), I prefer the M3. But for the road and the day to day slog, the massive torque of the C63 is really tough to beat.