Getting ready to do mine, also for myself. Able to use a lift at the place that maintains my 540i. The only thing I'm changing is to cut, relocate, and re-weld the trailer connector further upwards and underneath...therefore limiting that arched cut at the bottom and to each side of the reciever, still allowing for the use of the light connector. My goal is to keep the cut as close to the receiver as possible. We'll see how it go's
Talked to the dealer mecs. and they were cool with it. Said run all the wire but don't connect plugs...they would do that when they did the software crap.
The hole thing is a friction joke....although for those of u that have never held the receiver in your hands...pics don't do it justice...it's a beast! Nicely over-engineer-d!!!
Cant remember...Is it measure twice & cut once, or measure with a micrometer & lop it off with an ax