First, is the car a US Spec version. The federalization process could be a nightmare otherwise, possibly easier to part with it and purchase a new car here in the states. Otherwise you are fine if it meets US crash standards.

1. Doesnt matter, I have an European Spec RS4 cluster in my Audi S4
2. Someone else could help you on this
3. This goes back to what I referenced above, someone with more knowledge of the model could help.
4. What currency does Dubai use? Exchange rate?
5. I would assume the warranty is backed by the manufacturer regardless of where you are.
6. Insurance is up there. Depends on your driving record, age, etc.