[Sunroof]

For me I have had nothing but nightmares with my son's 1999 A4 with the 1.8T engine. Here's the heads up.................at 100k or thereabouts the gasket behind the oil filter housing is known to go. If that happens oil does not drip, it FLOWS out and if you do not stop when that oil light comes on you'll burn the bearings and screw up the crank QUICKLY!! To R&R the filter is a $100 fix and should be preventative maintenance early on. The 1.8T is known to suffer from "black death" or oil coking. If you do not have the engine checked out for that your screwed!! The oil gets way to hot because of the location of the turbo and the cat. converter (no shielding). Audi states..........you MUST USE MOBIL 0-40 or 10-40 or your dead!!!!!!!!!! The oil get so hot it cokes and plugs up the oil pump intake. They took off the pan of my son's engine and the pump pick up was clogged with debris so hard it felt like concrete and could not be removed. The pump was replaced and the lube lines cleaned at a costly sum. Audi's answer to the "black death"? Lets shield the cat. converter to deflect heat. So between, the coking, the oil filter housing gasket and a bunch of other crap, I gave up on buying a TT a while back or at least with the 1.8T. My suggestion is to get a thorough PPI at a dealer or reputable Audi shop and have all the items discussed thus far checked out.
There are a ton of TT's on the market these days and I would certainly take my time to find the one that was carefully maintained and that includes scheduled oil changes with Mobil 1. I would'nt get too compulsive based on a low price. These engines do have above normal issues and you'll pay dearly for a bad choice.

Bob