All right, I finally got around to cutting the hole in the diffuser today. It was nerve racking and ended up needing to be bigger than I originally hoped. This is for the torklift 2” hitch that has the removable receiver (the only one spec’d for the MK8 GTI). To be clear this is now installed on a MK8 Golf R.
I’m going to skip over the installing of the cross bar as that is pretty straightforward but you do have to remove the rear lights, bumper, and disconnect the ultrasound sensors. It’s all easy enough to do at home if you jack the rear end of the car up and pop the wheels off.
For installing the receiver you will need to cut a hole in the diffuser. The receiver (pictured) fits into the cross bar and is bolted in with a giant 4” bolt. You need to cut a hole in the diffuser to slide this up into the cross member. I started by using a bunch of masking tape and some magnets to help locate the approximate center of the socket on the cross member. I then used a combination of a dremel too with a cutting wheel and a rotozip to start to cut the opening for the receiver. Long story short after a ton of trial fittings and - what felt like - a million small cuts. I had the receiver bolted in.
The whole thing looked a little rough and I wanted to clean it up - this is a brand new car, after all. So I got some edge trim to put around the cut. I found that by so carefully tracing the outline of the receiver I couldn’t get the edge trim to conform to the many (many) bends. I made the decision to just make the hole a larger rounded square so the edge trim fit. As you can see it looks pretty good. I couldn’t think of anything better. Even cleaning up the cuts with a soldering iron didn’t look that great enough.
I installed my 1up bike rack and all seems good. This 2-piece hitch doesn’t seem as wiggle free as the hidden hitch I had on my mk7 gti and have on our mk7 tdi sportwagen, but I’m sure it’ll be fine.
The 2nd part of this install isn’t for the faint of heart. I’m not a car mechanic, but I do have good mechanical skills and do some woodworking so I’m comfortable and familiar with cutting tools and making precision cuts. That being said with the edge trim I think you could do a pretty hack job and still have it come out looking pretty good. Just take it slow and don’t reattach the two retaining clips that hold the center of the diffuser in until you have the receiver all torqued up - the 100Nm spec on the bolt is a lot the get done with a 15/16” socket in a cramped space.
I know I had a lot of questions about the fitment of this hitch so I hope this helps others who are in that situation.