BEagle
I use a Nokia Hands Free Kit in both vehicles, NOT connected in anyway to the TomTomGo.
Maybe I am getting old, but I find the traffic info on BBC radio more than ample, the sat/nav gets me there, and I have a phone to talk to people, all needs covered!!!
TomTomGo is great as a stand alone unit, I have not found any need to connect it to other technologies, I like to keep things simple!!!
Now that my reasoning is out of the way, to answer your questions;
the European maps costs about £100 for them all.
The unit connects to the PC via a USB connection and shows as a mass storeage device.
All the data is held on an SD card, obviously you may need more than one card depending upon which maps you have/use.
Before I bought the sat/nav I used MS Autroroute, now no contest !!!! Autoroute is great for use at home, but on the road it is very much a very poor sub for sat/nav.
CK