I just scored a good deal at Advance auto yesterday on a few qts of Royal Purple 15w40 (on clearance) so I picked them up for our 3 ATV's. You guys think this will work ok? The manuals all call for 15w40 or 20w50. both of my kids units are little polaris' and mine is a Suzuki King Quad 400. I've never used RP in anything before mainly due to its price but hear its decent stuff.