If you prep the cab, body parts etc and paint them before putting them back on the cab then everything looks nicer and you have a better final product that looks like you took it all apart plus you dont have to mask everything off while on the frame to keep frame wheels etc from getting overspray. You just have to be extra careful when putting the truck back together have an extra hand. Also before putting on the front clip you can install the engine trans and have less chance of scratching the fenders and hood etc.
