I've been putting drop in liner with a mat in my trucks since the '80's and never had the bed rust, I have run caps for the last 25 years though. if you throw a log, cinder block or brick in bed it doesn't dent or scratch the bed, bed sides or wheel wells. If I haul sand or mulch, I take it out a rinse the bed and liner, takes about 15 minutes. Below is a pic of my latest liner with the storage on the rear sides, 5-gal fuel containers and milk creates fit nicely in them. This a pic before the mat and ARE Z2 cap.
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