Spotted Castrol Edge 5W/10W-30 oil at my local Orly's. $8.50/qt list, $5.05 my cost
#19
It is a heavy 5w-40, esp in cold. BMW dealers have the Castrol 0w-40. GC really is the ticket...
run it hot and do a UOA. My guess is no probs. For srs duty, look for the PP 15w-50 or some people say they have seen 5w-50. Rotella Synth is another HD oil to consider.