First thanks for sharing more info.
Edit: The M3/M4 Technical Manual also has the differential information:
http://f80.bimmerpost.com/forums/att...5&d=1406475520
For those of you that wanted more depth to the operation and construction of the differential which is like that used in the current M5 here is a link to the full M5 technical PDF.
The differential section starts on page 42.
http://f10.m5post.com/forums/attachm...2&d=1360773149