Just bought a 2004 GTS, Previous owner was a just put in whatever is cheapest kind of person. The two things I know are incorect is generic power steering fluid being used instead of Dextron II, seals are leaking and I will have to tackle that eventualy. Cheapest unleaded fuel was also used, instead of 91 Octane. Dont know what problems that may cause. Pretty sure 5w-30 was always put in, just varying between Synthetic blend, Conventional, and full synthetic. Anything else I should look out for or do?