A stated wouldn't bother on the whole car, might as well save the cash for a proper respray.
I dipped my spare set of wheels in white a couple of years back and it held up nicely. No prep other than thorough cleaning needed. Then again I did follow all the usual spraying rules. Thin coats, drying time etc
long story short ended up using all summer with no problems until tyres needed changing then it peeled at the rim. Bugger to get off when hardened though only thing that seems to get it off is WD40!?