jtmstr: Music over bluetooth also works with my Pioneer DEH-P9800BT. It connects automatically but I have to start the media player on the phone and manually start playback. As it is, A2DP playback offer little advantage over having a seperate mp3 player hooked up to the AUX.

I suspect it should be technically possible to write a script that trigger when the car stereo connects to the phone. If so, starting the preferred playback program should be possible. That would be a great improvement.