[Shizznizz]

Easy check: If your diff flanges got 6 bolts, its a 188mm diff, if 8 bolts its the upgraded 210mm diff.
188mm diff on BMW race/drift cars were fine up to about 400hp, the 210mm are considered bullet proof regardless of the hp.. traction would be your limit, and even destructive drifting driving is not able to wreck them. They have stronger ring gears, stronger output shafts etc.
I've got a 210mm on my Backdraft, but its actually very rare and built on request. Their BMW subframe is only compatible with 188mm diffs as far as I know.