There are other things, but the truth is, you should probably ask over at HacktheIbus. They are the experts.
I have hearss you can use it to sense events in the car, like a door opening, or the lights coming on. You can also send text to the various LCD displays in the car, including in the gauge cluster and the radio. All of these things are by memory, and I might be incorrect, so check with them.
There are probably more things.