i wouldnt ever buy a performance car with an open diff to begin with........What true driver's enthus. would? Having an open diff to me is like destroying a car... it might as well just be automatic too.
I'll keep all you bmw newbs alert when i trade out my 3.15 diff for a stronger diff (3.46, 3.39) and let you know when i'm selling it.
Current standings: 98 M3 Track car
Mods: suspension, i/e/fly only
1/4th mile: 13.7@101 on 235/40 streets
Rd Atlanta: 1:44's on RA1's, 1:46 st.trs
95 M3 3.2obd1