All those biased 'tests' are crap IMO. Unless a truly independent party makes them, under real conditions, and with COMPARABLE OILS, it's a waste of time for most of us. Royal Purple should be compared to group IV oils, like Mobil1 extended performance, Pennzoil Ultra, etc., not lesser group IIIs, like regular Mobil1, Pennzoil Platinum, etc. Furthermore, if you change your oil regularly (not trying to get 15K miles), even group III synthetics are all you need.
By the way, I have RP on my tranny and differential, even though it's not 'approved' by BMW, so I obviously think it's a good oil, but probably not better than any other comparable (truly) synthetic. Good day.
Last edited by elp_jc; 10-30-2011 at 09:09 PM.