Yeah, it's large, but it does solve my toolbox problem. The brackets go almost all the way to my shackle flip, but no bolts are back that far yet. Next time I rip it all apart I'll pull the gas tank and tack weld some nuts in the inner frame and add a couple of bolts to the back (front?) of the bracket. There are no bolts on the top of the frame, but there is a truss of sorts on the bracket that fits up under the frame. Not bad for a $300 bumper w/ locking toolbox.
In the long term (whenever I move my shackle flip back for longer springs), I might even weld the DIY4x mounts to the bumper bracket, but I'd have to learn to weld first.
It's mounted up pretty well, 3 grade 8 bolts on each side, and I can hi-lift the hell out of the rear-end now. However, the estimated 200-250lbs lowered the back of the truck by an inch. Zero rates will be ordered today to fix that.
In the first pic, that's the case for my Ryobi sawzall. It's a toolbox, so it needs tools in it. :P