Hi MerciZizou,
Did you ever find out the answer to this? I am in the UK and I have the options for both which have very different prices but I have no idea what the difference is.
I saw an 09 coupe the other with iDrive Professional and Enhanced Bluetooth but no USB in the armrest so had a look at the options that I could try and get the dealer to maybe work with me on.
USB / iPod:
http://www.bmw.co.uk/en/topics/owner...ludGVyZmFjZSJ9
USB Audio:
http://www.bmw.co.uk/en/topics/owner...ludGVyZmFjZSJ9
Thanks