Hey guys/gals. I'm a "newbie" on this site but not on other sites. Have a '99 Ram with low miles. Going to replace the front and rear bumpers due to the rear has a rust spot coming through and the front has a dent from my ex wife. Anyway, was thinking of spraying like a bed liner on the under side of the rear to prevent future rust, maybe the front too. What would you prefer? Should I scuff the underside of the rear bumper before spraying it on? Truck is in good shape and want to keep it for a bit more. Have the front, rear, bumpers and all of the plastic add ons from LMC truck. Thanks!