I buy my oil from the dealer. With BMW CCA discount, it is $13.05 per liter.
Bav Auto has oil filters for $7.95 right now. I just ordered 8 (they fit all 3 Ms that I have).
'95 Alpine M3 LTW
'00 Dakar M Roadster
'02 Topaz M3
Red/White SRF #4 (Chassis 561)