For the Nav system to work in Europe, you only need the European Navigational DVD. The GPS antenna works anywhere in the world, as long as the antenna receives the satellites. GPS satellites are close to being global.
According to Audi after I had my dealer ask for me awhile back. The official response, is NO, it won't work. At least not with some changes.
Apparently the hardware used to read the european and US DVD's is region specific. Totally unlike BMW for example that work world wide as long as you have the correct DVD.
I have since found out that if you use a european DVD in a US Spec Audi nav system, you can navigate to POI's or saved destinations but will be unable to manually input addresses to navigate to.
Last week my dealer spoke with the local Italian Audi service center, there is something that they can do to the DVD reader that will enable it to properly work with Euro Map DVD's. They quoted a 200 euro cost to convert the hardware.