I did the M3 rear swap in June '20 in a 330 6spd 'vert. The complete M3 rear fits; rear sway, springs, control arms, etc. At first I kept the 330 shocks, now Bilstein Sports for M3 which are the same non-M3. I needed to also swap the drive shaft b/c the LSD M3 diff' is longer. Once mated w donor cars drive shaft and it's works w the OE gearbox. You absolutely need the subframe carriage along w the diff mounting points are different. Now the upper range torque is much more available. The RPM's did increase about 300 at 60 mph or 400+ at 75 mph. Nice trade-off.I was told m3 subframe and diff are different. Is that why fatter rear sway bar dont fit. Is the m3 rear diff ratio better? I think its lsd as well no?