Just a quick glance shows that those come in either +18 or -6 offset.
So, 8.5 width, plus 1 for the lips of the wheel gives 9.5". So the centerline is 9.5" divided by 2 = 4.75".
So, the backspacing on the +18 is going to be 5.5" and on the -6 it's going to be 4.5".
Stock 17" wheels are stamped 44.45 and the wheel is 7.5" wide so you end up with 6.0" of backspacing, just for reference when shopping.
So, a MB TKO wheel that's 8.5" wide with -6 offset is going to put the outer lip of the wheel 2.5" farther out than the stock wheel. You can use this to visualize what it'll look like on the Jeep.
And yes, the stock caps that come with the TKO are hideous. Ask for the optional center caps (the Chaos style caps).
~Lots of modded Jeeps and a Toyota 4Runner~
My favorite quote from the press release.. sad but true: "Chrysler claims its products, especially the Jeeps, can handle all sorts of terrible conditions, churning through muddy swamps, climbing mountains, and crossing rivers. Turns out they cannot even handle a car wash."