I am now using both their engine oil and six speed transmission fluid and am very impressed. Excellent premium products, especially the tranny fluid. I changed over from Mobil 1 just for a try (nothing at all wrong with the Mobil 1, a great quality oil as well). I will say that Spectro oils are much harder to find (here in Canada). I have yet to find a shop or store that actually stocks it so I always have to special order it.