The usb stick is in the picture above the lighter plug, its a sandisc and ts not much larger than the plug itself, its tiny. They are great for glove compartment USB plugs since it only sticks out maybe 1/16 of an inch. I dont have any other USB plug except on the dash, at least I dont think I do. The car remembers the USB stick info, not sure what the limit is, it will even play the same track where it was left off when it was removed and put back in a day later with no delay.
My Vette, sync equipped Mustang and Dodge truck (and PC of course) play the iphone/ipod fine with just the usual apple ipod cable. Once plugged in everything is controlled by the radio, same with the X1 with the BMW cable but not the regular apple cable.
Picking tracks is a PITA with the non iDrive, all you see is two lines of text so all you see is two tracks, same with folders and sub folders. Same with phone numbers in the phone book on your BT phone.