I am using part of a DrawTite hitch to hold my rear bumper on. The frame still flexes more than I like in the very back, and I even beefed it up a bit with rectangular tubing! I would run the rectangular tubing up further in the frame rails if I had it to do over, or run more tubing beneath the rails, but that would be tedious work.

The DrawTite is what caused the rail damage I referenced above. Came with the truck.

-Bill
'87 4Runner w/ '96 5VZ-FE, 'Red Chili II'
'97 Taco XtraCab 3RZ-FE, 'BlackBean'
TLCA # 13257, Rising Sun 4x4 Club Land Use Coordinator
"He who stops being better stops being good." -Oliver Cromwell