You know, the cheapest Walmart stuff. I used to get Castrol, Pennzoil, etc. but now I am noticing that the 1.8L Subaru is burning a lot of oil, about 1qt/700 and 2.3L Ford is almost as bad at 1qt/1000 so I am thinking what the h3ll, these are 10 year old near-disposable vehicles anyway. Will probably also use it in the 5.7L GM vehicle. Does using SuperTech vs. a better oil have any measurable impact on anything? My F250 however, will get the best dino oil I can find, probably Pennzoil. It is just as old but has a low-mileage newer engine. I think that thing can last a decade.