Just echoing the sentiments in some other threads: impedance matching into the AuX input is poor. Levels are quite low and I have to have the car stereo volume really cranked just to get decent levels. Is the fuze outputing digital MP3 data to the USB port while it’s playing? Do any care stereos have a USB port for input that will process it? Anyone tried an in-line headphone amp between the sansa and the car?
I’ve used USB with my Kenwood car stereo. It recognizes either MTP or MSC modes. In these cases, the car stereo is playing the music, and the Fuze is just storage. The Fuze will be in “connected” mode, so its menus aren’t accesible.
It’d be nice to be able to use the Fuze menus and just output to a cable that provides USB power and line-out, but no such cable is commercially available. It is possible to make one if you have a soldering tool and are willing to risk any possible damage to your Fuze that could occur if you don’t do it right (there was a recent thread about this). The only commercially available solution would be to buy a big dock and use it in your car.