Do you know that it WASN'T painted with Gatorback cladding paint? This forum made me aware of that option -- which sounds pretty decent.

FWIW, I saw a product at O'Reillys the other day called "Peeler". Description said removes paint while leaving undercoating intact. That might be worth a try. Another product said to apply and use forced air to release, but I forgot what it was called.

It might be worthwhile to try one of these products on a lower panel (kickpanels?) and try using a high-pressure carwash to release any paint. There might be a point where the pressure of the water would be enough to flex the plastic and cause the paint to "pop-off". If it doesn't, I might be inclined to try that Gatorback stuff over the top of paint -- to get a uniform result. (Feather any edges if necessary -- all uneven edges show under paint.)