I recently updated my GS2 i9100 from GB to ICS (4.03) as provided by my carrier (Bell). I am able to pair the phone and media audio with my car stereo (Hyundai Sonata) however I get the message "Unfortunately bluetooth share has stopped" every time it tries to download my contacts to the car. This appears after a minute or so.
This was not an issue with GB as it downloaded seamlessly and I was able to use the built in voice calling feature of my car with no problems.
The first time the download was tried, the phone rebooted. Since then I have removed the pairing from the phone and car and started over, as well as removed all synced accounts from my contacts except those actually on the phone. Still no luck.
I use this feature daily and will have to attempt a rollback to GB if I can't find a solution.