Holy smokes, this thread reads like a trainwreck. I'd return the car ASAP to the shady dealership that sold it in that condition. And I certainly wouldn't trust that same dealership to do any work, not even filling up the tires with air. From what it sounds like, that car is a ticking timebomb waiting to destroy your bank account.
I've owned used M cars in the past, and while some of them have been thrashed, the majority have been modless and driven like Camrys. The same can't be said of the cheaper performance cars like Evos, STIs, Nissan Zs, RX8s, etc. They've usually been modded to varying degrees of insanity and have been to hell and back.