My good friend and BMW Tech recently swapped the whole Bottom End of an E46 M3 into his E46 328i, if that helps.
2000 328i 5 Spd Black on Black SOLD!
2004 G35 Coupe 6 Spd Gray on Black Current
FS. JB Racing Lightweight Flywheel (Non-M 6 Speed ONLY) - $450 obo
FS. Spec Stage 3 Clutch Kit (Non-M 6 Speed ONLY) - $400 obo