I am planning on painting my 91 Mustang. First I am stripping it to bare metal and then I want want to apply the primer. I have to repair some dings so I was considering the epoxy primer because the filler can be applied over the primer and it is good to apply to bare metal. Also, can the plastic bumpers use the epoxy primer with a flex? Or should I use a urethane primer on the the plastic parts and a epoxy on the metal? Also, I was going to over reduce my primer for the sealer, so what primer should I use for the sealer?