idk if AMI is used when you're talking on your phone in the car, and if it is, it should be compatible. Check your owner's manual. My gf drives an A4. It's not fully loaded, so I don't think it can do that. But your car being an A6, I would be surprised it you didn't have that option.
Do you have a newer A6 with Bluetooth A2DP streaming support? In my 2006 5 series BMW (which does not support Bluetooth audio streaming) I had to get Blackberry Bluetooth Gateway(around $40) and now I can play any audio from my Torch using AUX input in my car wirelessly.
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