It depends on the date of manufacture of your head unit, and where you live! BMW sells a unit, and other products are available that are more complicated yet more functional. Head units built date later than 09/02 or with software version 43 or higher can do aux input. The MODE button is not a good enough of an indicator to check if a radio is AUX or Sirius compatible. To check the software version: 1. Turn Radio Off. 2. Turn Radio On. 3. Press and hold the "m" button for about 10 seconds. 4. Press < or > to navigate, you will need to go to the 2nd screen to look for the SW Verison which is in a SV xx-xx xx format. 5. To be Sirius/AUX or XM compatible, the radio must be SW 43 or higher. 6. Turn radio off to exit. Check out this link: http://forum.e46fanatics.com/search.php?searchid=13811430
