I was considering a fiberglass cap until I realized the payload tag for my '06 2500 4WD QC LWB is "only" 1,943 lbs. That's not alot when you load fuel, my better 1/2, 3 dependents, their gear, and the trailer tongue weight (600 lbs?). Probably within specs but another 200 lbs or so won't help the cause.