So i have Spotify on my AVR, PC, Android Mobile, but not in my car. Not a big problem, just connect the phone via bluetooth.
Works like a charm, the only downside, the Song/Album/Artist information is not transmited when using the spotify android app. A quick test with the default android player shows that this works perfectly. I see song/album/artist on the car display.
So please, add this functionality to the android app. (to spare you the search implement A2DP/AVRCP 1.3 :-)