While you chaps try to work out the maths, I'm concentrating on my comfort. I think I've just about got on top of all the functionality in the car including voice control of the satnav (Audio 20). However, has anyone managed to get music onto the Garmin SD card that the Audio20 Garmin Map Pilot maps sit on? There's about 13GBs spare memory on there so I thought I would fill it up instead of stealing back one of the USB slots from my children. I put a folder on the card called "Music" and copied a chunk of iTunes content into it but the Media screen says something like "no memory card inserted" when I select it. The card file format and music file formats are all supported according to the manual so I can't see why it shouldn't work. Anyone cracked this?