Wjang hit it right on the head, do a slow burn, that fast burns leave too many errors that might be corrected on your home unit, but cannot be corrected in the car head unit.. Also check with the burner manufacturer as to what cd-r's they reccommend to use, they do make a difference, as well as some head units are finiky towards certain brands also..
couple links to help out..http://www.gum.de/it/download/english.htm
http://www.fadden.com/cdrfaq/
