I am also interested in this subject. When I was forming my company in Podgorica/Montenegro I asked my POA this and he answered very simple; there may be some issues like; the cars in USA has turning lights indicators flashing all red at the rear, because of this when you turn right/left all the rear lights are signalling. But in Europe we have separated orange color turning indicators. So There maybe some issues registering US Spec cars on road legal because of the electrical system of the car. On your Audi case here, you better ask to some car import/export'er and they will clearly answer your question.
And you can share it here hopefully.
Faruk