Tig welding 101
Tig is really better for doing panels. A mig will do most of the same work around a car.
If I was buying something, miller syncrowave 250dx Lincoln squarewave 255 would be two machines to look at. They are expensive.
mygwenevere - Wade would be a good guy to ask, he does it all the time and is a kick *** welder. He likes the new Miller Dynasty, $$$$$