The wiring is easy, just get a PWM taillight converter, several company’s make them and wire up a normal 7 way plug. The brake control is a little harder, I made all my connections behind the spare tire except for the brake “trigger” wire which comes from the LCM. I don’t remember the pin or wire color but it is the center high mount brake wire you tap into. Remember to put a 20 amp circuit breaker on the BC power supply and a 30 amp breaker on the charge line. I used to wire up cars/trucks to tow at a rv dealership and have done several x5’s of all generations this way. As far as the hitch is concerned, I agree the best hitch’s are the factory ones and you can find them frequently in the junk yard, just be sure to get the bumper support brackets when you get the hitch itself, the wreckers don’t usually take those with and they are different then the cars without a factory hitch. You can still find “factory style” that bolt behind the bumper supports and don’t have the ugly bar that goes under the spare tire, you just have to look for them. I went this route cause at the time I couldn’t find a factory hitch. Because I worked in a fab shop I built and installed supporting brackets to accompany the hitch to get the rating of the factory one, perhaps a little more.

Good luck
Dave