Well look at tradition.
E30 M shared something like 2 -3 body panels from non-M version.
E36 M3 used virtually all the same parts except for slight cosmetic things (rockers, mirrors).
E46 M3 uses doors, roof, trunk from non-M version, all other body parts are unique.
So it would be LIKELY that the E90 M3 uses mainly different body parts than the non-M coupes.
'95 Alpine M3 LTW
'00 Dakar M Roadster
'02 Topaz M3
Red/White SRF #4 (Chassis 561)