Bought e39 2001 Lemans blue. Will post pics when the car gets here. I want change out all fluids engine, tranny, diff. Searched the forum found how to get this done. The engine will get oem fluid. The tanny, diff want change with royal purple. Here's the advice I need. Should I get oem fluids or royal purple is better because I see a lot of owners use this oil, but they they folow up with this remark that gets me thinking. Change to royal purple xxxxxx of miles ago still running good. Please advice me on this question. :confused2