Expensive oil doesn't stay any cleaner than cheapo NAPA oil. Oil stays clean because you use a good filter and your engine doesn't have a lot of sludge buildup, not because the oil cost more. In fact one the jobs oil does is carry impurities out of the engine and into the filter. There is a lot of hype concerning oil these days. If you change your oil regularly and use a good filter your engine will last a long time. Any good quality oil will do. Personally, I use good old Motorcraft oil and filters and I change 'em every 3k. Unless you race or put a lot of stress on your engine you don't need to spend $5-$10 for a quart of oil