Technologically advanced,[3] the 300 was regarded as a "driver's" car, sharing numerous design innovations and mechanical components with the iconic Mercedes-Benz 300 SL "Gullwing", including engine, suspension, and chassis.

Twin downdraft Solex carburetors and an innovative diagonal head-to-block joint that allowed for oversized intake and exhaust valves produced 115 PS (85 kW; 113 hp) at a 6.4:1 compression ratio.

Designed to give reliable service under prolonged hard use, the engine featured deep water jackets, thermostatically controlled oil cooling, copper-lead bearings and a hardened crankshaft.

[4] The combination of a rigid X-shaped ovoid steel tube frame and four-wheel independent suspension provided surprisingly nimble handling.

An innovative dashboard-operated rear load-leveling suspension engaged a torsion bar to increase stiffness by one-third when needed, and a pedal-operated central lubrication system kept friction points silent.

A total of 6,214 saloons and 591 Cabriolet Ds, retroactively referred to as the "300a" series, were produced through September, 1955, including a brief 300b run incorporating elements of the 300c's partial facelift prior to its debut.