I am Sooooo Confused over Paint

^^^ I agree. Clean metal, epoxy primer, AND topcoat that with urethane primer AND topcoat with whatever, on the floors, etc Good ole thick and heavy Rusteoleum enamel works great! IF not floors, topcoat with real auto paint, acrylic urethane, enamel or bc/cc. Screw POR15!
I used rustoleum on my floors both inside and put, trunk, gas tank, inside of the fenders and all my suspension parts . Works pretty good for a driver quality rig.