I can help you out on the issues as well....
Nikisil Vs Alusil (spelling??)
Make sure its the later for the 4.0 V8, the 3.0's from what I hear did not have this problem...(says my mechanic).
Thurst arm bearings love to let go (I fixed those last month)
Cooling system is a bitch (I fixed that on mine two months ago)
Other then that not much else I can think of other then the normal stuff that could break on a car that age. But generally as you know a Bimmer is a tad more to maintain then most cars...