Welcome onboard, I understand how you feel because I was the same until I finally got it. Below are some answers to your questions
1. should I get EU or US
Really plug and play is only the US unit. The EU unit incolves modifying the US map DVD and it has some minor dificulties displaying certain road types. navigation is not affected at all as far as I can see so far. If you are fine with modifying large (2.8GB) files and if you are able to create a dual layer DVD, if you don't care about OEM XM or AM, then you could get the EU unit and save $1k or more.
2. is it Plug and Play?
I installed my unit in a couple of minutes, getting the GPS antenna wire hidden took the most time. The plug and play adapters you can order from several source are fine if you specify exactly what you need. I did not need to change any wire when upgrading my Symphony II with Bose to the EU RNS-E
3. if not, what kind of plugs/adapters do I have to get (please provide some links on where where I can get them, if you dont mind)
Check out the cables/adapters section here for sources. Kufatec is one, Ralf Deventer is another source, they are both on ebay.de or you can contact them via email
4. if not, how much re-wiring is involved?
As I said, in my case (2004 A4 B6 Avant) nothing but getting the GPS cable from the radio slot to the dashboard
5. will I have to wire/route the GPS antenna to the shark fin? if so, how?
I would recommend to get a new GPS antenna and mount it either on your dashboard (between the windshield and center speaker) or under the dashboard behind the instrument cluster or on top of the glovebox. IMO it's not worth the effort to get a cable routed through the whole car just to get the signal from the shark fin antenna.
6. I read it on one of the threads that on a B6 A4/S4, that you don't have to find the speed wire. Does this mean that "speed info" is being sent to the RSN_E unit through one of the existing wires behind the Symphony II?
If you get the RNS-E part number 8E0 035 192C (EU unit) or 8E0 035 192E (US unit) you get all signals over the existing CAN-BUS connection. No additional wiring required.
7. I live in Seattle. Does anybody know what shop I might be albe to get this installed at?
I would recommend to start with Justin's installation pictures here http://www.navplus.us/forum/viewtopic.php?t=70. If you forget about the speed wire and the whole process dosn't look to difficult to DIY then do it. You may need to find a (friendly) Audi dealer or someone with a VAG-COM to check/update your settings but the installation itself should be pretty straight forward.
I hope this helps, good luck!
1. should I get EU or US
Really plug and play is only the US unit. The EU unit incolves modifying the US map DVD and it has some minor dificulties displaying certain road types. navigation is not affected at all as far as I can see so far. If you are fine with modifying large (2.8GB) files and if you are able to create a dual layer DVD, if you don't care about OEM XM or AM, then you could get the EU unit and save $1k or more.
2. is it Plug and Play?
I installed my unit in a couple of minutes, getting the GPS antenna wire hidden took the most time. The plug and play adapters you can order from several source are fine if you specify exactly what you need. I did not need to change any wire when upgrading my Symphony II with Bose to the EU RNS-E
3. if not, what kind of plugs/adapters do I have to get (please provide some links on where where I can get them, if you dont mind)
Check out the cables/adapters section here for sources. Kufatec is one, Ralf Deventer is another source, they are both on ebay.de or you can contact them via email
4. if not, how much re-wiring is involved?
As I said, in my case (2004 A4 B6 Avant) nothing but getting the GPS cable from the radio slot to the dashboard
5. will I have to wire/route the GPS antenna to the shark fin? if so, how?
I would recommend to get a new GPS antenna and mount it either on your dashboard (between the windshield and center speaker) or under the dashboard behind the instrument cluster or on top of the glovebox. IMO it's not worth the effort to get a cable routed through the whole car just to get the signal from the shark fin antenna.
6. I read it on one of the threads that on a B6 A4/S4, that you don't have to find the speed wire. Does this mean that "speed info" is being sent to the RSN_E unit through one of the existing wires behind the Symphony II?
If you get the RNS-E part number 8E0 035 192C (EU unit) or 8E0 035 192E (US unit) you get all signals over the existing CAN-BUS connection. No additional wiring required.
7. I live in Seattle. Does anybody know what shop I might be albe to get this installed at?
I would recommend to start with Justin's installation pictures here http://www.navplus.us/forum/viewtopic.php?t=70. If you forget about the speed wire and the whole process dosn't look to difficult to DIY then do it. You may need to find a (friendly) Audi dealer or someone with a VAG-COM to check/update your settings but the installation itself should be pretty straight forward.
I hope this helps, good luck!