if you get a professional shop to do the painting you'll be fine and the panels will be fine ~~ just have to find a shop that knows what they're doing ... when painting flexible surfaces you have to mix in things like plasticizer, flex agent, etc
Yeah, I saw a pretty tricked out Element a while back. It had the composite panels painted to match the rest of the car. It looked pretty natural, like it was supposed to be that way. Took away the unique look, in my opinion, but it didn't look technically bad.
Almost any bodyshop should know how to paint plastic. Almost every car has plastic bumpers these days. Saturns have tons of plastic on them. If a company does the job and it all falls off, I'd demand a refund, because there really isn't any reason for that.