I always prefer the shells uncut for spraying, they are far easier to handle and far less chance of getting overspray on the shell. Buggies are easy to cut out too, just follow the lines, with a sharp blade, then snap and cut, bobs your uncle. TC shells, I just mount the shell over the chassis (on mine), pilot holes for the body posts, then spray up.
http://academyracer.fotopic.net/ for any inspirational pictures