I have glassworks front fenders on my truck and have been having a lot of stress cracks in the paint. When I get my bedsides, I plan on getting the fronts repainted. Is there a special paint used on plastic body panels that could be used on fiberglass to allow the paint to flex with the fiberglass rather than cracking? Or do they just put a flex agent in the paint? I want to prevent the stress cracks this time around.