I did this before any boat buying, but thought it's worth a post too. After getting quoted $3000 for a trailer hitch installed from the dealership, I was determined to do this myself. Looking online, it didn't seem like an overly difficult job, but still it required removing the bumper.
I purchased an aftermarket wiring kit that was super simple to install. It did not require any splicing of wires, and took only 2 hours to install. The Wiring kit: https://www.amazon.ca/gp/product/B01CKQJCBY/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
The hardest part was testing the factory wires to see what colour was what using an electrical voltmeter tool: https://www.amazon.ca/gp/product/B002JGQAQ6/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
Once I got the wiring kit all working, turned my attention to the actual trailer hitch. I have a 2019 BMW X6, and the process for this vehicle is pretty simple - remove the fascia bumper, unbolt the factory rear bumper frame and then reattach the new trailer hitch / bumper frame to the same connection.
I purchased the actual hitch from etrailer.com for $350. They have a ton of great videos and resources on their site for DIYers: https://www.etrailer.com/Trailer_Hitch/Curt/13077.html
Instructions for hitch installation both aftermarket and factory are below:
I also purchased a kit to help remove the bumper fascia. These little tools were very helpful vs ripping it apart with a flathead screwdriver like a savage: https://www.amazon.ca/gp/product/B085NVRVS5/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
Wish I took more pictures than I did, but here's the begging and end. All in this hitch installed and wired probably cost me $600
