whoa... i felt so alone on this. I thought i was the only one. I have a 7/05 build. I've been pulling over every now and then when i am not in a rush to check out the sound... and have been embarrassed as people who pass by may wonder wtf is wrong with that new bmw (2006 model still is new *2yr form prod date* IMO) I rev the engine.. slowly and aggressively, hoping to fix it. I mean its not so much of a loud sound... its just noticeable when i park sometimes and walk out with the engine on. When i am driving i don't really hear it whether i have music up or down.... when i visit my dealer in 2 weeks I will have them check that out, also I know i do need an oil change. Lets see what happens..
... but i doubt that would do anything..