I have been using royal purple, Mobile 1, and now Fuchs synthetic oils. 5w-30. I get the royal purple and fuchs at discounted prices. How does amsoil compare to fuchs and royal purple? Can you PM prices? is it possible to buy it in 5+ quart jugs, gallons, 5 gallons? Pleas let me know. I am close to an oil change and it will be Fuchs or amsoil