I owned a 325xi e91 and didn't experience any turn signal problems, same for my current 420i F36. Lot of German cars (VW, Audi etc) have a two stage turn signal. A light bump will do 4 or so signals and automatically stops if you move the stalk all the way it wil stay there until you move it back.

to me the sound is loud enough to hear it but not so loud it is annoying