There's going to be a big price difference for one thing.
The 63 coupe will compete with the M3, not the M1. Mercedes/AMG doesn't really build a competitor to the 1 series. The new C-class coupe is not much of a looker like the E92 is.... in the spy shots it looks tall and boxy.
BTW 7200 rpm redline on the 6.2l is good enough for me