UrS6,
With a very conservative "chipped" tune it is absolutely a beast. (400awhp/440awtq at the wheels) If it wasn't a one off, I'd sell my Avant and daily the RS6. Tall 6th gear has little pull until 80mph but makes for quiet cruising and great fuel mileage. Click into 4th or 5th at any highway speed and instant torpedo. There is definiately more of the engine's power getting to the ground with a manual versus auto. Auto is probably quicker out of a hole on a launch (with me driving the stick) as I don't launch (aka abuse the tranny), the manual is superior in every other regard IMO. LWFW is not an issue with a custom tune, throttle blips, heel toe, etc are smooth and seamless, it acts like a stock MT car.
I know you were asking ttboost, but I had to interject. ;-) It's my new favorite car!