Just fitted mine, excellent instructions on this thread and others. Thank you to srhutch for working this out for the M, I've been considering paying someone to do this since I got the car 10 years ago.
I can't add anything to the instructions but one potential pitfall is when removing the two LCM connector blocks from their holder to check the pin numbers before cutting the wires. I test fitted them without reinserting them in their holder after I'd wired everything up and the bulb warning light came on. After wasting a lot of time checking and double checking my connections, I discovered that I'd bent a couple of pins within the LCM when I test fitted the block. Once they were straightened out everything worked perfectly.
My parts were purchased from Sopers who were first class.