You may/will need to:
Change intake system and probobly fit an intercooler if one os normally fitted.
If an ECU is used, it will need to be updated ro changed, otherwise fuelling may need to be adjusted.
Vacuum lines will need to be added/rerouted for any wategate. You will need to lay on an oil supply and possibly water too for the turbo.
Exhaust will need modification, so you'll want the manifold, turbo and probobly the downpipes, possibly the whole system.
This is off the top of my head from the list of mods on my own VAG 10VT engine.