Along with iPhone 4 Top

I use the receiver in my car along with an iPhone 4 and the BMW Professional audio system (2 subwoofer and 8 other speakers). NGC. the 3.5mm output of the iPhone is the sound quality better, because you even at higher volume has less noise. The bass is great, it would buy again. Prima also with an iPhone navigation app like Bosch, so you listen to music and this is lowered during speech as a permanently installed navigation system.
Beautiful is also that a simple can connect by clicking on the button with the iPhone and can then skipping between pause / play and alternating with LongPress. In the beginning I had it once, that the reception was dull - but I could never reproduce again, from the next day (perhaps from / to ??) it was always top.

Conclusion:
Top sound quality without cable, particularly with the iPhone top!