Autozone Their touch up paint section is pretty good and spot on.
I disagree...it was way off on my car
http://www.grandprixforums.net/my-06-gp-gxp-72403.html OBX headers, TEP tranny cooler, ls1 IM fuel rails and injectors, ls2 TB, ls7 MAF, full custom exhaust, Quad retro headlights, full out front and rear suspension work, tuned by HPT by me 8====>
What color? I have artic white and there was no shade difference once I matched the paint code. Now if a panel has been repainted at some point in time I can see it not matching.