Pretty much all cosmetic modifications. You'd have to go through and buy all the black trim pieces, black lettering (unless you want the debadged look), dark tail lights, etc. etc. You can find the parts for sale at various sponsors of this site, eBay, Amazon, and other places. When in doubt about how something looks/works, cruise through your local dealership's lot, and take a look at the Altitude models. I frequently find that physically looking at something, rather than at pictures, is the best way to rid yourself of doubt.
2014 Jeep Grand Cherokee Limited 4x4
5.7L Hemi V8, Luxury Group II, Navigation
Hemifever Tuned, Billet Catch Can, 265/60R18 Hankook Dynapro ATMs