Audi also is setting the Boxster as its performance target which is a pretty lofty goal. Will the TT really match the mid-engine Porsche? Chances are it won't but at least they are setting the bar high. The main thing is the chassis setup will likely provide for more feedback and better handling than the current car. Feedback from the chassis typically being an Audi weak point. Oh, and expect aluminum to reduce the weight too.
Engine choices will likely mirror the current offering except that a 1.8 turbo will be introduced to go with the 2.0 and that the 2.5 turbo inline-5 in the TT-RS will be reworked for a bit more power. Expect the car in 2014.