I did the curt hitch and tekonsha harness install yesterday (Curt 13420 hitch, Tekonsha 118784 harness).
It probably took a couple hours in all, including removal of the lower hitch cover and trimming it - it's not a job for the timid. I ended up using a buzz wheel and finished with a file for a cleaner cut.
Some hopefully helpful tips for anyone taking on this project:
-the winch for the spare is on the rear passenger side. 11mm head, turn clockwise to lower and counterclockwise to raise the spare
-you can access the bolts for the passenger side of the hitch by unhooking the two rear exhaust hangers, but it's a beast getting to the bolts even with exhaust lowered slightly.
-the hitch cover panel can be removed by removing the two push clips, then releasing 4 tabs on the sides. There's also two philips head screws that need to be removed from the support brackets. The remaining 6 clips are then released by pulling the panel straight down (it takes some oompf to remove them.)
-the Tekonsha harness is listed for a
Sorento (IIRC) but it works perfectly. Release the factory harness cap by squeezing the rearmost part of the tab, then pulling the assembly apart.
-see pics for tools used. Fasteners are all 11, 17 and 19mm.
-I used loctite blue for all the hitch fasteners, though red may be better. (I just happened to already have some blue in the toolbox so that's what I used.)
-one other suggestion is to cover the shiny side of the hitch cover panel in blue tape before removing it, as it's easily scratched. I only used blue tape around the cut, but should have done the whole panel since melted plastic went everywhere when I hit it with the buzz wheel.
-the curt instructions say to use tin snips to cut the panel, but I found a buzz wheel worked better. You could also use a dremel with a cutting disc.