Everybody rants and raves about POR. They should call it POS because I never liked the way it worked. For the floor pans I guess it's ok but on the frame or suspension parts, funk that. Use a roll on bed liner. Not only will it hold up bitchin, but it will also act as a sound deadener. Your call man just giving you my opinion from years of painting and restos. About 6 years ago a buddy and myself restored a 70 split bumper camaro and sprayed the front subframe with POR 15 and after 2 years of Sunday driving there were huge flakes of paint missing exposing the epoxy primer. I won't use it on anything, not even my lawn mower.