Royal Purple turns to regular amber after about 2 hours of driving.... If you looked at my oil now it looks like regular old oil.....
I have used both Mobile 1 and Royal Purple, and don't notice a difference, other than the RP has been cheaper lately.....
I don't see the point of running 5w-30 instead of 10w-30, cause at all temps above 45* they are very similar if not the same viscosity, and Id rather have the 10w(thicker) protection in the freezing temps than the 5w(thinner)(a good oil will leave a film, and 5 or 10 should arrive at the same time once the engine is turning)
