The engines are bulletproof as long as there's oil and coolant. The auto transmissions are a whole different story. I think VW/Audi have always had problems making long-lasting autoboxes.. The Audi 5000 was notorious for breaking the transmission, and I once replaced the transmission on an Audi V8. The is AWD and the transfer case and front differential is integrated. This makes for a 4' long and 300 lbs thing. Luckily, it lasted for almost 200k miles with proper maintenance. The rest of the car still feels like new, there's no rust and the 4.2 liter V8 pulls strong.
I've owned several Audis, and I have to admit that the cars from the late 80s and early 90s are the best. They have some "personality" that the newer ones don't have, and they have mostly gotten rid of the quirky electronics from the mid-80s. (read: they bought a HVAC system from GM, it's also found in 80s Cadillacs!) I enjoy Audi a lot too, but a lot of the spare parts are either ridiculously expensive or NLA. With Mercedes, parts are relatively cheap and I can get everything. They make durable autoboxes too, but for me it doesn't matter if I drive auto or stick.
BTW, here in Norway, a Jetta like that, even with all the leaks, would probably be worth $3-4k due to an extreme import tax on all cars.
