hey, i was in pepboys today to get oil for my ranger 4.0L. and they have that 300000 mile Valvoline engine guarantee. i've used mobile 1 the whole time ive owned the truck and i was considering switching over for the guarantee. the shop i used to work in used mobile one on the whole fleet and the stuff worked wonders. i was wondering if anyone had any opinions on Valvoline or this guarantee they are offering.

thanks!