Gloss black for plastic!

I am painting a plastic golf cart this week and have a question. I was going to paint the roof a gloss black (customer wants it) and the rest of the cart in a metallic carolina tarheels blue (light sky blue) with some air brushing. I was going to just use the same PPG omni plus basecoat black and clear it on the roof but now thinking to save the customer money just use SEM or some kind of spray can black that is GOOD and will LAST and not peel on plastic.
Any recommendations here? The biggest thing I am worried about on this job is this darn plastic and it making the paint peel or crack. It's flexable and that waxy like plastic that you cannot sand.
Thanks for any information!

the roof will get so hot out in the sun .bad idle . and if you can get it to stick it may not stay looking like a roof it could wrap all to hell . a lot of that waxy plastic when made has the release put rigth in the plastic so by painting it black evey time it gets very hot it the paint may have a hard time hooking on the plastic from having the release in it

I would recommend a system called Bulldog. It is used by many painters to get a grip on problem plastics.

What is Bulldog? Even if I use regular auto PPG paint the roof will have problems? The roof isn't the waxy kind of plastic, the body is. I was told I can use SPI Epoxy primer right over the plastic after cleaning it and do two coats of that, sand it, one more coat and then spray basecoat.

well is it Smc then you can paint it with any thing.if urethane like a bump cover then you can use a epoxy like dp and ppg paint. if you do not know what you have you can call the maker of the cart or cut a very small sliver of the roof were you can not see it and do a burn test. if burns like a candle then it is a waxy type of plastic. if just has small clear bubble and you have to work more to keep it burning it is urethane . but there are many more if you can not hook in to it with your finger nail then you should be good to use a epoxy Hot rod can help you more on this maybe

Like Pat said, depends on the type of plastic. Some will take regular paint, some won't.

I would call the manufacturer to find out what it is, then consult with your local paint store for product info.