I have done BT retrofit on mine 2006 E90 from bimmernav last year and it works fine
Except voice commend it still in German
I tried two dealerships to recode the car
with instructions from Martin no luck. I was with Martin on the phone 4 times, last time he offered me to rent a tool called MOST optolyser but without cables (big help)
So now I am looking for basic voce commands in German