[FazdaGt]

If you are in PA: You tell the notary that your are swapping cars even up. They ask you to assess a value to the cars (make sure you say both are worth the same amount) they fill out a form that gifts your car to the other car and his to you. No taxes paid, just notary and title/registration fees. I've done this many,many times with no issues, as long as you go to a decent notary things should be painless.

Feel free to pm me if you want me to elaborate.