LukeADE,
Sounds to me that you have knowledge about these diffs.
You mentioned that the E36 M3 uses the same one, I did notice that there rear case plate has two rubber mounting points, do you think the rear casing is interchangeable between the E30 and E36.

Any other thing I need to know about, like the friction plates giving problems, weak bearings etc, etc. I read that they recommend a certain Castrol Synthetic oil optimize for these LSD's.

The other thing I would like to know, is it possible to adjust the amount of slip on these, did pickup that you get different sizes metal plates that the friction plates slides against, could this be to compensate for warned parts or to adjust the amount of slip/lock.