From `2009` to `2011`, the `S4 Avant B8` changes the tone of the line completely: the naturally aspirated `V8` is gone, replaced by the supercharged `3.0 TFSI` with `333 hp`, which is fuller, quieter and much easier to live with every day. Against a BMW 3 Series, it plays the role of the very fast estate that can absorb motorway work, town use and family loading without losing real pace. On the used market it can look more rational than a `B6` or `B7`, but it is no more forgiving of vague maintenance.