I had forgot about this thread. More below.
http://www.e90post.com/forums/showth...ight=rpms+idle
The video on this thread sounds the same, just with the non-stock exhaust obviously.
http://www.e90post.com/forums/showth...ight=rpms+idle
This one sounds the same too, particularly post 19 where flukey says he can instigate the stutter with a throttle blip. Also post 39 mentions it's worse when it rains. I think mine is too.
http://www.e90post.com/forums/showth...ight=rpms+idle