The Nascar boys use this product.
http://www.crracing.com/racing_perfo...formance.shtml then check out the GOLD REFECTIVE FILM. The color is not my first choice but I have used it on aluminum panels and was simply amased. I have tried many other products with varing degrees of results but this stuff is great. It figures the boys with a gazillion dollar budget would find the best stuff. I have also had good luck with the 2 foil sided jutting that is about 5/8 total thickness, but the key to that is seal each side or top and bottom if you make a cut for fitting. way cheaper but not as good.
Good luck Jeff C