Just went through and read the whole thing. You just need to start rebuilding the whole car with NEW parts and sell the for a lot cheaper Morons sit back a million miles away or from next door and diagnos problems and dont have a clue. You didnt give him no warranty Raymond? I would be embarrassed to bash someone after buying a 16-20 yr old car and there was some issues. WTF do people expect? If a buyer doent know how to buy a used car and doesnt ask to have it inspected by a qualified 3rd party then the old "tail light" warranty applies. If he would of had it inspected and there was issues that you could of resolved before it left your posession to make buyer satisfied or if you didnt want to mess with it, this would give him the opportunity to negociate the price down some. As a grown up, you make an decision to buy something and it turns out not to be to your standards, then its your baby.
BTW those headers didnt work out we traded the seats for 6 months ago, I want my seats back!!!

Maybe Midiablo can give you and I some political speaking, people person skills lessons