Between `2003` and `2004`, the `S4 B6` changes the tone completely compared with the `B5`: less turbo, more displacement and a lot more mechanical presence. Against a BMW 3 Series, it leans on the `4.2 V8`, `quattro` and the feel of a compact saloon with a big engine. It wins people over quickly, but it needs a far stricter inspection than its discreet looks suggest.
The centrepiece is the `4.2 V8 BBK`, depending on version and market with a `6-speed` manual or `tiptronic`. The engine can be excellent when oil supply, cooling, ignition and usage were healthy, but you need to read the rear-mounted timing chains, cold-start behavior, oil consumption and ageing ancillaries realistically. Good cosmetics never replace a sound technical base.