Get over to
Forza forums to learn how to do this. P.S it takes A REALLY long time as you have to do tedious placement with simple and complex designs when painting youre car. Eventually you'll figure it out. When you get to the website, (if you're not already at the forums) just look anywhere in the "forza motorsport 2" section. NONE of the paintjobs can be bought off the marketplace, all of them have to either be made or bought from the FM2 auction house. P.S if you buy them, be prepared to spend major $$$ for good ones.