I raced a 2010 C63 Sedan (no power pack) with my 2013 Lime rock, it was a very close race, but the C63 had the lead, by a very small gap. I've owned a C63 Coupe before Sandy, and i can tell from experience that the M3 will lose badly ahah
I still like the M3 better tho, my navi in the C63 sucked and the sound system wasn't as good. but i loved that pannnno roof it made it. plus i had to go get new tire's every time.