My suggestion, find the highest point where you can trace the oil. Unless the oil was splashing everywhere, which usually means a pretty big disaster & hole in the wallet, the highest point is probably where you need to pay attention.

My $.02.

__________________
01' 3.0i E53 (M54) with 164,000 miles
07' 3.0si E83 (N52) with 134,000 miles
08' 3.0si E70 (N52) with 91,000 miles