Autotrader.com
KBB.com
You should start looking online at a site like autotrader.com or cars.com. They will show you a listing of cars in your area that meet your needs.
There are quite a few places you can look to find A4 cars, but you can look at "Used Cars", if you're looking for a used one and the cars official website if you're looking for a new one.
Jaguar car can be imported and exported anywhere in the world
Most cars now days are imported to the US. Any Japanese, Korean, or European cars are imported. Not all brands are imported, however. Some Hondas come from Canada, and some VW's come from Mexico. So "what is imported to the US?" is a very vague question.
Cars made outside your country that have been shipped to your country.
The things imported are: ~Gold ~Medicines ~Cars ~Electronic Items and ~Perfumes
In my experience, the best website to find what you are looking for would be Kelley Bluebook. This website can give you all the information you need about cars.
The US Department of Energy offers a very enlightening fuel economy chart for all the cars in the USA and the ones being imported and you can visit their website for information as well.
If you are looking for used cars, try craigslist. If you are looking for new cars there is a website that gives you discounts on new vehicles and you take it into a dealership and they give you the car for that price! It is called Drive Your Dream - it is awesome!
Collector Cars are actually available throughout the eBay and amazon sites via private sellers. You will need to do some hard looking though as people are insecure and don't want to get scammed.
I depends on where you live as to where you can find one. The best place to find imported cars would be in Miami or Los Angeles in America. There are no special regulation for buying import cars as long as they are in America when you purchase them.
You can visit the DMV website for your state. This is going to give you a listing of all cars that are registered as having a handicap license plate.