Just did a couple tests with my iPhone pairing the phone to cars with bluetooth enabled navigation systems. I paired with a 2007 Range Rover and a 2007 Chrysler 300 SRT. Both paired pretty easy, you do need the correct pin number (usually 4 digits) to the cars navigation system. After that it only takes a few minutes. Made some test calls on both cars as well, both worked fine. BMW is suppose to support this as well, on some models. I have heard of people pairing with Audi but with some troubles and failed attempts at times. Not all car navigation systems support this feature with the iphone.