[Got Insulin?]

I only have limited experience with it, but I know that there is some rediculously high-temp clears and powders that you can get that will hold up to the realitively small amounts of heat generatedby the average car. Exh. mani is a different story entirely...
However, that's why I mentioned clear powder, too. I know that depending on the applicaion, it's strength and temperances can be quite a bit in front of any paint or clear you could use.