Have been testing the Astell&Kern AK120 high resolution mobile audio player and must say not only does it work great with the stock Bentley Adapter/USB, the AK120 sounds far and away better than the iApple input ever did! Controls are the same via steering wheel or track fwd/back on the lower center console. CD selection 1 through 6 also seem to work, same as iApple, but again better sound using only the UBS to AK120 versus the iApple device. Also, the system seems to be far more responsive during track or CD 'disc' changes too.