Only thing is, remember that violations of the Clean Air Act are CRIMINAL offenses. Not just a fine, but possible jail time. Your choice.
A Turner Stage 4 engine kit gets about 70 HP gain and is perfectly legal.
'95 Alpine M3 LTW
'00 Dakar M Roadster
'02 Topaz M3
Red/White SRF #4 (Chassis 561)