I've got the same problem as you and mine started happening after 1000kms (at 2400kms now). I only started noticing mine when in sports mode and going over a bump and a left hand turn. It's now gotten a little worse and now happens in comfort, regardless on whether you are turning, although it is still mainly bumps, not potholes. It more noticable if you run over a couple of small bumps close together.
I have VSS and am not sure if that's a contributing factor. Took it into the dealer a couple of weeks ago and was able to replicate the problem for them. They're ordering a new steering rack from Germany, and it should be here in the next week or two. Reports from this thread, http://www.f30post.com/forums/showthread.php?t=740055
indicate it may not be the solution. Apparently it's fine for a week or two then the noise returns. I'd find a section of road which you can consistently replicate the problem before taking it in. Mine was as easy as the dealership driveway .....
I'll let you know how I go with mine, but a response that the noise is normal isn't going to cut it. If they can't fix it, I'll just keep getting them to order me a new steering rack every 2 weeks until they find a permanent fix. Or they can replace the car!
Thankfully I don't have any problems with my brakes, but there was a post on the main forums about squeaking brakes, http://www.f30post.com/forums/showthread.php?t=747374