[cmn]

Hi guys! I just picked up an '06 E91 320d this weekend to serve as my daily driver. So far it feels great, except from a bad rear shock absorber (ordered new ones), and a really annoying rattle. I tried searching, but couldn't really find any great results/answers.
It's a metallic rattle, and it seems the rattle is coming from the front of the dashboard in the area around around the center speaker. It only occurs at idle (or at least very close). It is not the blower motor (which I think has been replaced earlier).
Any ideas where/how to start searching for this annoying sound?

Thanks in advance!