OK here goes. I put a new bumper cover and upper bumper (made of urethane, I believe) on my truck about a year ago. I painted it with adhesion promoter, basecoat and clearcoat (from cans from automotivetouchup.com) After wetsanding and buffing it looked great. The problem is the paint is very vunerable to bug guts and hard water eating into it. I'd guess its probably laquer. Now I want to redo it in a urethane paint (using professional products) and I need to know what is the best method to prepare the surface to be repainted. I have heard that a good scuff sanding and then using an epoxy primer would seal the laquer to accept a urethane paint. My concern is that epoxy primer won't flex enough to work well on these parts. Any suggestions?