I installed a rear hitch on my '15 Macan S. My intended purpose was for a bike rack, so I didn't do the wiring harness. I went with an OEM setup because as a thru bumper unit, it provided the most ground clearance and significantly higher tongue height over any aftermarket under bumper hitch. I was impressed with the build quality and strength of the OEM unit. It is a heavy gauge tubular steel welded construction that weighs at least 40 lbs more than the lightweight aluminum extruded rear reinforcement it replaces. My impression was that any occupant would be much safer in a rear end collision if they had the OEM hitch. It bolted right on using the same bolts.
Even though I used my 2 post lift, the trickiest part of install was R&R of the cover, which was kind of fiddly and needed 2 people to line it up accurately while removing it and again sliding it into place. Be very careful not to spread the cover outwards very much during this process as the plastic can crack by the tail lights. Then you get into plastic welding and painting. (I know this first hand)
I also had to purchase and install the black plastic lower rear valance that is clearanced for the hitch. (Cheap)
I found reasonably priced used hitches for sale on eBay, etc, but by the time you factored in freight and packing, it was cheaper and easier for me to buy it at wholesale from my local dealer.
The rear impact bar assembly seems to be worth about $100 on eBay if you want to factor in cost offsets of reselling the old parts.