Full disclosure: we're dealers for Expedition One. And the whole reason we became dealers for them was I wanted to run their rear bumper on our JK. I've known James from ExpOne for many years through my own forum and remember seeing the designs for their bumpers back when they were just CAD models. At the time, they were also the first and only company to offer a tire that opened and closed with the tail gate. And frankly IMHO it's still one of the best looking JK rear bumpers out there. I originally installed the bumper and did the write-up in early 2010, and to date have had no problems or rattles.
We got one of Expedition One's front Trail Series JK winch bumpers along with the rear bumper, and everything was packed into one big, heavy box. The bumpers and tire carrier were individually wrapped in plastic, then surrounded by expanding foam. It did a great job protecting everything during shipping, but I felt like an archaeologist digging for dinosaur bones trying to dig everything out from the foam though.
The hardware and small parts (tire mount, coupler, tail gate coupler mount, etc):
The instructions are great and include photos to help with the assembly of some of the parts. They're online on Expedition One's website too, and they've even got an install video on YouTube.
The factory JK rear bumper mounts to the frame with two bolts per side, plus an additional two bolts on the backside of the rear crossmember. Our JK's previous owner neglected to reinstall the crossmember bolts when we swapped the factory bumper back on to sell the Jeep, so four bolts is all it took to pull off the big plastic stock bumper. Keep those four bolts, you'll reuse them to install the Expedition One bumper.
JKs are definitely designed differently than previous Universals.
Oh, quick recommendation -- the instructions tell you to pop the vent panel off the inside of the tail gate in order to disconnect and remove the CHMSL wiring harness. Don't do this. Well, don't do this if you want or need to keep some kind of CHMSL to stay legal. Instead, remove the torx bolts holding the plastic light assembly to the metal tire mount and clip the wiring harness up near the light.
Here's a shot showing the reinforcement inside the bumper ends and how the massive tire carrier spindle sits down into the bumper and reinforcement bracket.
That vertical rectangular block is the backside of the 1" thick d-ring tabs. The driver-side of the bumper has matching bracketry (just no tire carrier spindle of course). With the exception of the d-ring tabs, everything on the bumper is made from 3/16" plate.
So, on to the install!
Before you fit the bumper to the Jeep you have to place the supplied L-bracket nut plates inside the frame rails so that they line up with the rear-most hole in the frame rail.
Now just hoist the bumper into place and loosely screw the bolts in on either side. You'll reuse the four factory bumper bolts (two on each side) plus an additional larger supplied bolt at the rear. The forward holes are slotted so you can adjust the fit of the bumper as needed. It's a bit awkward getting the bumper into place if you're trying to do it by yourself, so if you've got a buddy you can bribe into helping you, do it.