A couple of answers:
If you have Bose you should code it for Bose. If you code anything else it may conflict with the Bose EQ/AudioPilot. There is a TSB on how to disable the AudioPilot and enable DSP/GALA. In this case you would code the proper sound characteristics for your car. AFAIK, GALA won't work unless the AudioPilot gets disabled (wiring change at the Bose amp). Once you disable the AudioPilot and enable GALA you can set the level the volume increases dependent on the speed increase. This can be done via VAG-COM or under SETUP on the RNS-E, so it doesn't matter which value you initial set.
Digital radio is the DAB in Europe. In the US you want to code Satelite radio if you have the 2nd generation XM or Sirius receiver.
Your Phatbox is nothing else than a CD changer, so coding a CD changer would be correct. Can't tell you much about the harness/adapter you need for your Phatbox execpt that three wires will need to go the sat reciever in the back, the other wires need to go to the RNS-E's CD changer pins. You may want to follow this topic where Todd is working on getting a custom Sirus/Phatbox harness made for his RNS-E: http://www.navplus.us/forum/viewtopic.php?t=837
If you have Bose you should code it for Bose. If you code anything else it may conflict with the Bose EQ/AudioPilot. There is a TSB on how to disable the AudioPilot and enable DSP/GALA. In this case you would code the proper sound characteristics for your car. AFAIK, GALA won't work unless the AudioPilot gets disabled (wiring change at the Bose amp). Once you disable the AudioPilot and enable GALA you can set the level the volume increases dependent on the speed increase. This can be done via VAG-COM or under SETUP on the RNS-E, so it doesn't matter which value you initial set.
Digital radio is the DAB in Europe. In the US you want to code Satelite radio if you have the 2nd generation XM or Sirius receiver.
Your Phatbox is nothing else than a CD changer, so coding a CD changer would be correct. Can't tell you much about the harness/adapter you need for your Phatbox execpt that three wires will need to go the sat reciever in the back, the other wires need to go to the RNS-E's CD changer pins. You may want to follow this topic where Todd is working on getting a custom Sirus/Phatbox harness made for his RNS-E: http://www.navplus.us/forum/viewtopic.php?t=837