Water pump and timing belt, also do the serpentine belts and a new thermostat, timing belt normally comes as a kit so make sure they do the tension springs as well.
1.8T's are pretty bullet proof, they suffer mostly from water problems, leaking hoses mainly, the one at the back of the engine is a pita to do if you have a quattro.
My Turbo just blew at 266,000 miles, kicking out loads of smoke but other than that i have had 3 cam belts and i chuck in any old oil i can find, even mixing mineral and synthetic haha, but as others have said... Servicing every 10k miles or 1 year will keep it up together, oil change is dead easy and a new filter costs peanuts.
Fuel pumps can fail, expect 250 quid from a dealer to do that, coil packs are known issues and mine needed a new starter motor at 150k miles, i never changed a clutch, exhaust, wheel bearings nothing even the brakes lasted me over 100k miles lol
Car still drives like new except for the turbo issue and is much nicer to drive than my new 2008 320d sport
