I am happy to report that the retrofit is done and was a success!
With the help of everyone on here and Alex I now have fully functioning OEM bluetooth and voice command.
Running the mic wire from the MULF to the FZD only took about 2 hours with both of us working on it. Without the help and having to figure it all out on my own as I went probably would have taken me about 5 or 6 hours.
One strange thing has happened and that is that I was using the BT perfectly, stopped off to run an errand, cam back to my car after about 30 mins, and the car wouldn't pair with my phone, and nothing I could do would make it pair. Checking both the phone and the car, turning the phone off and on, turning off the ignition…etc.
So I let the car sleep for 20 or so minutes and reset then tried again and it was all fine again. I guess it may just do this from time to time and i probably shouldn't worry about it, but has anyone else had this?
2009 e90 335i