We carry the
BMW 8 Gig Flash Drive, it is formatted fat32 out of the box, and works with the USB systems in the X5, 550i, and M5 from my personal experience. On my 8 gig flash drive I can put nearly two thousand mp3s, the load time isn't even worth considering. Something to take in account when going to a large drive such as a 64 gig is load times. I have a 32 gig flash key at the house with a lot of mixed media on it, that particular key took a noticeable amount of time to become ready to use.