I have the same head unit with the BOSE system, no other upgrades, the Jabra "Cruiser 2" unit, and an iPhone5. The audio (MP3, Pandora, video etc.) is very good. The volume is a little lower than a regular CD, or FM so you do have to be aware when turning off the Bluetooth, but it is not dramatic. The telephone sounds a little strange coming out of the car stereo speakers, but not because it is bad, just different/odd having the caller in stereo. I do find that I sometimes will have to turn the stereo up when talking on the phone, but again it isn't dramatic.
I am sure the sound is not as good as a it would be if there was a direct input, but I am not sure how much of a difference I would possibly notice since the topis down almost all the time, and I can't really tell the difference between it and playing a CD with the top up.
Of course my wife will tell you I can't hear anything anyway!!!
