I am not really sure which color to use, since I havent done any 97-03 gp's, only 04+. BUT, In my experience the regular color coat is the way to go. It is what I use everytime, unless it is a 100k+ show car, then I get them professionally painted.
here is a link to where to get it, plus the online chart doesn't suck ba**s. SEM Color Coat For Vinyl, Leather, & Plastics