Maybe some of you have realized this installation tip already, but I'll bet like me, some have not.
After installing the BT module in my X3 and using it for a few months, I was getting frustrated with having to repeat myself all the time for people to hear me.
I looked at the microphone and realized that the little piece of cloth lining the microphone grill was still installed - presumably to keep dust out. The mic has its own, so both were not needed. I removed the cloth from the grill, and now people can hear me loud and clear.
The installation instructions say nothing about removing this cloth. They should. The difference is like night and day to the people I call.
Andre