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I don't know about MCU2 vehicles, but prior to MCU2, the USB ports are only USB 2.0, and music+dashcam works on AP2.5 MCU1 vehicles. Also, USB 3.x may emit the same frequency as Bluetooth (2.4 GHz), causing interference, but this is only true when actually operating at USB 3.x speeds, so a USB 3.0 device shouldn't cause problems in a USB 2.0 port. To your question, the key thing is to make sure the device you get has high enough read speeds for the music you want to play (unless you're playing uncompressed lossless audio files or using dashcam/Sentry functionality, you probably don't need to worry about any of that).