Re: iPhone connection
The NG4 does not have bluetooth audio streaming.
As tianorth mentioned you can connect your phone audio jack with 3.5 mm to composite cable to the connector in the glove box.
However, owners typically copy their music to a USB flash drive and play from that, or copy music to the 10GB HD of the NG4 and then music play from there.
Be aware though that when you revert to factory settings, all music is wiped from the HD so I would recommend to get a large USB flash drive (I mean large in capacity, they are very small in size nowadays) and copy your music on there and leave it in the USB slot under the armrest permanently.