I got a 2006 X3 two years ago (2010) for my wife so we're well out of our maintenance period but when i checked the cabin air filter it looked pretty bad. I would hazard a guess that it may never have been changed in 60,000 miles or was maybe once.
I like to stick to Mann or Hengst filters. Here's a little write up I did on replacing it on X3 models with links to the Mann filter I used on Amazon:
BMW X3 Cabin Air Filter Change DIY Guide
Save yourself some money and get the parts yourself and install it ...takes 10 minutes and you can have peace of mind that you're not being ripped off...
That is obviously overkill for simply changing a filter but i wanted to document the process so anyone thinking about doing it could see how easy it is.
Last edited by jvest2000; 11-30-2012 at 03:28 PM.