Congratulations to your new car. You said "it was recommended to have the Navi put in later", did the dealer recommend that? I'm just curious because so far Audi's official answer is No, retrofit not possible. I'm wondering if this has changed.
Anyway, some answers to your questions:
1) The Euro 8E0...D and H units have not been updated yet. maybe one day someone with a D or H will give it a try. It is also not certain that the Euro SDS (voice command) will work with the US software. Chances are good that the Euro unit with the US software will do the same as the US unit when being connected to the US phone interface. Any other combination is pending verification by someone who spends the money and tries it.
2) It is to early to say if there are any issues further down the road. the 2005/2006 US DVD has not been released yet and nobody has the US 0040 software update CD to verify that it will actually update the Euro unit running the US software. The 2005/2006 US DVD is supposed to get released soon and I'm sure there will be some trying what happens in regards to updating the software.
3) The original 2004 US DVD will work with the 0020 US software loaded onto the Euro units, no more file editing required.
4) To early to answer. For all your BT questions follow the topic under Multimedia.
5) All A4 are SAT radio ready and should have a shark fin which does GSM/GPS/SAT. As far as I know, all A4 shark fins support all three signals.
6) GPS is for navigation, GSM for the phone interface and SAT for XM/Sirius, all in the shark fin. Besides that you have up to for AM/FM antennas in your rear window(s) which are connected to amplifiers and a diversity box. This diversity box gets connected to your radio/Navi via 2 antenna wires - HF and ZF. Both wires are required for good reception, if you leave diversity/ZF off your signal strength will drop and you will find less stations when scanning. You only need one GPS but many have found it to be easier to put a new GPS antenna behind the instrument cluster instead for routing a new wire back to the shark fin. However, in the helpful links topic there is at least one S4 Sedan which has the shark fin GPS connected to the Navi.
Have fun...
Anyway, some answers to your questions:
1) The Euro 8E0...D and H units have not been updated yet. maybe one day someone with a D or H will give it a try. It is also not certain that the Euro SDS (voice command) will work with the US software. Chances are good that the Euro unit with the US software will do the same as the US unit when being connected to the US phone interface. Any other combination is pending verification by someone who spends the money and tries it.
2) It is to early to say if there are any issues further down the road. the 2005/2006 US DVD has not been released yet and nobody has the US 0040 software update CD to verify that it will actually update the Euro unit running the US software. The 2005/2006 US DVD is supposed to get released soon and I'm sure there will be some trying what happens in regards to updating the software.
3) The original 2004 US DVD will work with the 0020 US software loaded onto the Euro units, no more file editing required.
4) To early to answer. For all your BT questions follow the topic under Multimedia.
5) All A4 are SAT radio ready and should have a shark fin which does GSM/GPS/SAT. As far as I know, all A4 shark fins support all three signals.
6) GPS is for navigation, GSM for the phone interface and SAT for XM/Sirius, all in the shark fin. Besides that you have up to for AM/FM antennas in your rear window(s) which are connected to amplifiers and a diversity box. This diversity box gets connected to your radio/Navi via 2 antenna wires - HF and ZF. Both wires are required for good reception, if you leave diversity/ZF off your signal strength will drop and you will find less stations when scanning. You only need one GPS but many have found it to be easier to put a new GPS antenna behind the instrument cluster instead for routing a new wire back to the shark fin. However, in the helpful links topic there is at least one S4 Sedan which has the shark fin GPS connected to the Navi.
Have fun...