[3] The M256 shares a modular design with other inline-four and V8 engines, which are all 500 cc (31 cu in) per cylinder.

[4] It uses an aluminium alloy block with dual overhead camshafts and has 4 valves per cylinder.

[5] The M256 uses a 48V electrical system to operate a BorgWarner electric supercharger,[6] which can spin up to 70,000 rpm to reduce turbo lag.

[7] In the S 500's G variant engine, an integrated starter alternator also provides up to 16 kW (22 PS) and 250 N⋅m (184 lb⋅ft) of boost, and replaces the drive belts by managing the water pump and air conditioning; allowing for a smaller and lighter engine.

[8] Engine output excluding the additional 48V system boost available on the S 500:[9]