Hi, I recently began experiencing similar symptoms, perhaps not as severe. Not seeing any codes yet. No jumps in rpm either. Today my car runs fantastic, no indication of a past problem whatsoever, but I expect the issue to come back.
http://www.e90post.com/forums/showthread.php?t=691932
In addition to what was suggested to you here, there are replies to my post that lean towards what your dealer is thinking.
Thanks for suggestions made here and any others in the future.