For the stickers that actually say Saleen, I believe you need to have an authentic # for one. When my X was building my Capri into a Saleen Mustang wannabe (bastard!), he had to supply them with a verifiable VIN or # of some kind. I don't know about now tho. He had a friend who owned a Saleen and he just used his #s.
Don't put stupid Saleen stickers on your car. I'm not saying the stripe on the bottom of the car, but the actual Saleen name on your car. It's not a Saleen, and never will be so don't do something lame.