I have an audi 80 TDI.

Problems on high milers like mine is they tend to burm oil caused by
the valve stem seals. Oil leaks around the sump.
Water pump goes as do the radiators but they can be replaced easily.
Done a water pump in under an hour, plenty of space to get to it.
The one thing to look for is the alternator belt tensioner pulley
(plastic), they tend to go around 100k, but can be replaced for under
£25, hardest part is the putting back on the belt, you have to take
the tension off the pulley by pulling down the wheel using a spanner.
Cornering is a bit wully, but you get use to that.
Electric windows modulators go, but i got one of ebay.

Changing oil filters are a complete swine to get at, after you have
undone the filter you have to slide it out by going down through the
engine bay and
then under the car, i tend to rest the oil filter on the cross member
then crawl under the car and retrieve it. Still haven't found a better
way after numerous oil changes.

Interiors are good and body work very good.
I average 45 mpg at 80 mph.

weakest part of the car is the brakes, replaced several calipers as
they stick and freeze on. Costing around £65 each, not that expensive.
Usually shop at my local accessory shop or eurocarparts.

Heated front seats are fantastic. Not all models have them, look for a
slider button on the dashboard in the middle.

Overall not a bad car, running mine into the ground as i can't find
anything better without forking out at least 5-7k