https://motorsporthardware.com/product/78mm-black-bullet-nose-race-stud-kit-14x1-5/ here is the kit I'm using, it doesn't stock out past the base of the wheel itself. If you look up at the photos. I think the 78mm length is just right. Allows for 10-15mm spacers if needed.
Anthony C on FB MK8 group has his harness kit, which might be one of the best kits out.
Only issue with USP harness, is that it's got the brake light switchback for signal light, which isn't how the EU tail lights suppose to behave.