M3Pilot09, have you resolved this problem? I know that there are several posts on this but most of them discusses MY08 it seems.
My 2011 M3 E92 DCT has also developed this problem since my break-in service just this past Friday. It's irregular in frequency and goes away if the car is not running.
I had the dealer check this issue yesterday and their foreman told me that this did not sound right. He had four other technicians listen to the noise and could not quite figure out what/where it was.
They booked an appointment for me this Friday for a full diagnosis, which I assume will take more than a day. They also informed me that in their opinion the car is safe to drive and, as the noise appears to be external, I am in no danger of damaging any parts. Notwithstanding, I don't plan to drive it until I drop it off on Friday.
Another thing that I noticed, which I haven't told the service people yet (but I do plan to) is that the noise does increase in frequency when I do move from a standing position, but it does not appear to be related to any revv'ing. If I rev it slightly while motionless (i.e. N), the frequency does not increase, but only when the car starts to move.
Anyway, I would love to find out what happened to your issue. Thanks.