What has to come off FIRST:
-Lock carrier(radiator support assembly)
-Intercooler(if Turbo) plumbing
-Passenger side timing cover
-Center timing cover
-Thermostat housing(replace IF plastic - it will fail!
..see pic below)
To get clearance from the timing belt, either GENTLY twist it 90 degrees, or better yet - turn crankshaft w/ 24mm 12-point socket and breaker bar counter-clockwise, while a friend GENTLY pulls TB forward, about 1/2 inch, at the passenger-side cam sprocket and tensioner. BE CAREFUL not to allow belt to come off...or, it's GAME OVER(full TB service mandatory!).
Here is what a 2.7T Audi allroad plastic thermostat housing looks like after 160k in HOT Southern CA(nearly COOKED motor!):