Royal Purple says their oil leaves a film, which is important in lubrication? Any other oils that are known for leaving a good film, im using M1 EP 5w30 but if the oil is that good I may switch over. In a couple months when I change my oil I will get an analysis, Im thinking about putting cheap dino/filter on until I get my results back and then decide what oil I will use depending on the results. What other advantages does Royal purple have?