From `2003` to `2004`, the `S4 Avant B6` occupied a very specific place in Audi's range: a genuine family estate powered by a naturally aspirated `V8`. Against a BMW 3 Series, it answers less with pure agility than with a rare mix of space, sound and mechanical character. That makes it highly appealing used, but also the kind of car where emotion can easily hide the real technical risk.
The key issue is the `4.2 V8 BBK`, paired with a `6-speed` manual or `tiptronic` depending on the car. As on the saloon, the rear timing chains, cold-start behaviour, oil consumption, cooling, ignition system and ageing ancillaries all need a serious read. On the Avant, you also need to consider the tailgate, boot sealing, rear-end fatigue and the fact that many examples alternated between daily duty, heavy loading and fast road use.