Has anyone used Royal Purple oil in their scoob? It is really popular in America and seems to be the number one choice in the states. It is stocked at AAS, Newcastle at £56 for 5 quarts. F1 cars use this oil now instead of Mobil and on the racing scene it is used very widely and gaining popularity. Most Subaru owners in America comment on how smooth the vehicle as when using Royal Purple. Any comments or advice will be appreciated!