I converted my DW's Subaru and my (temporary) Sienna to use USB flash drives for audio. Basically, the electronics look like a CD changer to the vehicle's stereo system. For hers, I can have up to 8 playlists, each holding 99 songs each. For mine, I can have an unlimited number of playlists holding an unlimited number of songs each.
This makes it very handy and requires little storage to carry hundreds of hours of music categorized in whatever way we choose. I simply make MP3 versions of the songs and arrange them in directories.
Does anyone know of an aftermarket device for either the Chevy or Sprinter units that would allow us to do this?