All I had to do was use my 1x30 belt sander and round the square mounts, it fits nice and tight. Stock body, I am in the process of modifying the stock bumper to fit in between the bumper and chassis. So that I have the tabs (holes) for the rear body posts. If that doesn't work and it will, I would manufacture angled L brackets from Kydex and attach to the rear rx (fuel cell) box. All that is left for me to do is sand the bumper down a little and maybe open the holes for the mount a little more. It already fits nicely but I want to have the bumper as tight as I can to the chassis. To make the holes in the bumper, I used a hacksaw to cut the two mounting post off flush with the inside bumper opening. Then I marked and made a starting hole with my x-acto knife (broke my tip) Then I used my drill press starting with a small dia. bit and drilled through the mounting post. I used bigger bits till I got to 1/4" and then I used a round file to finish it up.