If you are working in the US then you have another option: Personal import. If you reside overseas and own a car over there providing you have owned it for 12 months over there you can bring the car in to the country and not pay duty. There may also be some loop holes for rego with an older motor if it has already been registered in tha other country.
I did it years ago with a Motorcycle I owned in NZ. It was a Honda NSR250, a model that wasn't sold in Australia. I had the bike for sale over there but wasn't having much luck selling it so I decided to ship it across. I rode it over here for a while and then sold it. Because it was a rare bike at the time when I sold it I pretty much got back what I paid for it and the cost of importing it.
Check out the Department Of Transport And Regional Services DOTARS web page
DOTARS
Cheers
edit: Cameron beat me to it. I went for coffee and pressed the post button when I got back.