We had a 91/H Audi 100 2.8E that was a lot of trouble.
Replaced it with a 96/N A6 2.6 that never missed a beat. 85k miles in 3 years, never needed anything other than routine maintenance (i.e. oil change every 12,000 miles). No rattles, no parts failures, no nothing. A very reliable and well built car. Definitely the most satisfying car we've yet had (current fleet includes 2 x MB, Porsche 996 and Range Rover).
NB: the car also had excellent climate control.
1999 SL 500
1993 320 TE
1986 500 SEC