The oil filter cap is held in place by a 10mm bolt, and i think the drain plug is well. My car's had other work done on it the last couple of times it needed a change so I havent changed it in awhile. if the drain plug is not 10 its 13.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>