Glad i'm not the only one with this problem. I also have a 3 week old 335i xdrive msport and i noticed brake squeal right after applying brake force before i come to a stop. I figured it would eventually go away after a "brake-in" period, but even after numerous attempts of braking hard, it squeals those few seconds before coming to a full stop. Kinda embarassing, especially with a new car.
Looks like i'll be making an appt. with my dealer for this soon.