Are you talking about pinstriping or something like it on the sides of cars? I think most people just wax over them, but if they're really large I'm not sure... I don't see why you can't use a vinyl protectant on it if you want.
Umm actually I was just kidding. But you sound dead serious in that case go to wally mart go to the paint section pick up a 3 inch foam paint brush spray the paint brush with 303 and cover your racing stripes. BUT i would try it on a small section first to see if the wax will go over the vinyl without acting funny because of the 303. I would imagine though if you cover your stripes with 303 every month you wouldnt need to wax them.