ooops I made a grammatical error on that lil picture.
It should read "untill it looks like the red circle"
The TT vents cost $50 a pair from your Audi Dealer the last time I checked and if you install them this way they remain fully functual.
here is a pic installed with some additional directions.
This is where the Nub used to be it needs to be removed to allow the new TT vent to sit in deeper and still allow the vent ring to turn.