S 400 d

The S 400 d sits at the top of the diesel range for the W223 in this model year, before the arrival of the S 450 d with its 367 hp in 2023. In this generation, the difference with the W222 is first felt inside: a 12.8-inch vertical OLED central screen that absorbs almost all physical controls, a standard 12.3-inch digital driver display, optional 3D display and augmented reality head-up display. The red upholstery stands out from the usual black, beige, and brown trio in the range.

Mechanically: OM 656 D29T R SCR, 2,925 cm3 inline six-cylinder, 330 hp and 700 Nm from 1,200 rpm, 9G-TRONIC gearbox and 4MATIC all-wheel drive. 0 to 100 km/h in 5.4 s, limited to 250 km/h, 177 g/km. The S 400 d does without the 48 V network found in the petrol versions: less electric assistance, one less expensive component.

The parameter that most changes the use of a W223 is the rear-axle steering, offered in two angles, 4.5 or 10 degrees. On a body over five metres long, the wide-angle version reduces the turning circle by up to two metres, dropping it below eleven metres in long wheelbase form, and changes the car's urban usability. The AIRMATIC air suspension ensures the ride; the standard configuration is a three-seat rear bench, with individual rear seats remaining an option.

A particular feature of this generation is worth knowing before choosing between two examples: Mercedes sells some functions as upgrades that can be activated after delivery, including the wider steering angle for the rear-axle steering. Installed hardware and activated function are two separate things, and the latter must be purchased separately from the manufacturer.

On the tax side, the CO2 penalty due at first French registration follows the scale for the year of first registration: at 177 g/km, the 2022 scale comes to 6,375 euros before the monthly reduction under article L. 421-7-2, applicable since 1 March 2025, far from the 40,000 euros reached by an S 580 of the same year. The regional tax for the certificat d'immatriculation (carte grise, French registration certificate) is 60 euros per fiscal horsepower in Centre-Val de Loire for 2026. Finally, a Euro 6 diesel qualifies for Crit'Air 2 (French low-emission sticker), an equivalent petrol for Crit'Air 1: this matters for daily use in low-emission zones.