BMW M6 (E63)
Why 5.5: 507 PS from a naturally aspirated V10 spinning to 8,250 rpm, under a carbon-fibre roof — and a car that woke up in a 400 hp mode every time, because BMW decided the full output was not an everyday setting. Rod bearings, SMG pumps and throttle actuators have handled the depreciation since.
Layout
Natural habitat
Ride comfort
Sound
Ten cylinders, individual throttle bodies and 8,250 rpm, and BMW never built anything like it again; fully extended it is the closest a road saloon has come to a racing V10. Grand-tourer insulation and an exhaust that stays polite below 4,000 rpm hold it off the exotics.
10-cylinder · naturally aspirated · 8,250 rpm redline · rated 8.9 / 10 for engine sound
Market value
Median asking price, good condition · €89k (2006) → €37k (2026), trending down · illustrative data
Child seats · ISOFIX
ISOFIX was spreading through these years rather than fitted across the board — whether a given car has rear anchors depends on its year and market.
Children were expected in the back. Front-passenger ISOFIX effectively didn't exist in this era, and airbag deactivation was patchy — treat the front seat as a no unless a specific car proves otherwise.
Derived from production years and seating layout, not a per-car source. ISOFIX was standardised as ISO 13216 in 1997, required on new EU model types from 2011 and on all new EU cars from 2014.
The long version
The S85 is the reason this car exists. BMW built a 5.0-litre naturally aspirated V10 for the E60 M5, individual throttle bodies and all, and put it in the 6 Series with a carbon-fibre roof, a 7-speed SMG-III single-clutch gearbox and a Power button that had to be pressed on every start before the engine would give more than 400 hp. It is a magnificent engine and a slightly confused car: too heavy and too insulated to be a sports coupé, too firm and too busy to be a relaxed GT. The United States alone was offered a conventional six-speed manual from 2007, which is now the version everybody wants. Then the running costs arrived. Connecting-rod bearings need replacing on a schedule, the SMG hydraulic pump is a known failure, the throttle actuators are expensive and the fuel consumption is comic. Values fell from ninety-odd thousand to under thirty, and stayed there long enough that the cars now belong to people who accepted the maintenance bill going in.