Excellent:
Thread number one by this guy:
"Thinking To trade my c63 for m3"
http://www.m3post.com/forums/showthread.php?t=461945
Thread number two by this guy:
"C63 to ///M3?"
http://www.m3post.com/forums/showthread.php?t=494196
Thread number three by this guy:
"should I just get M3? I have a C63"
http://www.m3post.com/forums/showthread.php?t=522198