In my experience the extra warranty will only last your till about 75,000 and thats where more expensive things start to go wrong. I just has to get the Cat replaced at 84,000 miles, $1600 including labor
Also $379 to replace the battery, freaking ridiculous. But I didn't have time to mess with doing it myself, and the places around I called don't have Audi batteries.
My suggestion, skip the warranty and buy a new car in 2 years.