It really is so simple to do. I'll post a link to a video in another post below due to the fact that I have to have 10 posts before the board will allow me to add links. lol
I can listen to SiriusXM, Pandora, and the music player in the car and on the earpiece without any problems. I even hear all of the sounds the phone makes when you scroll though various functions.
I wish I knew who you reached to accomplish this. I've called Global Support 4 times only to be told each time my S3 cannot be used on my trip to Ireland (GSM network) They said it would be up to 12 months for the update that would allow it to be global.
Like others, nothing OTA here in NJ for me. I did install Kies on my Win 7 box this afternoon and it immediately found the update and applied it with no hassles. ICS is running great.
I have 2 BMW's. In the car I'm told it sounds just fine, but in the SUV, everyone says it sounds like I'm in a wind tunnel as you say. I think it depends on the system in the particular vehicle in this case and not the phone.