Just did the install following alan's diy and it was a breeze. Snapped a couple of pics to supplement Alan's wonderful guide
OEM diffuser
Remove the OEM diffuser by undoing 5 push pins on the bottom and then pull the diffuser outward.
Undo the passenger side bumper to get access to the adaptor and swap in the M5 one.
All the wiring and comfort access strip transfers over to the new adaptor with no problem. However, there are two sensors that do not have a spot on the new M5 adaptor so I just used 3M double sided tape and taped it behind the locations in the red squares.
Install the insert onto your M5 diffuser. I painted mine gloss black to match.
Snap the diffuser/insert combo back onto your OEM bumper and start putting your bumper back together. The diffuser/insert has 3 screws on the bottom that can only be screwed on once the bumper is re-installed onto the car.
Have a beer and admire your new diffuser
