The SSKL was not offered through the ordinary Daimler-Benz sales programme but made available exclusively to competitive racers. It evolved directly from the SSK, which had itself been developed to address the handling limitations of the earlier S and SS models on tighter circuits and hillclimbs. Where the SSK used a shortened 2,950 mm wheelbase and the enlarged 7.1-litre supercharged straight-six engine from the SS, the SSKL went further by systematically lightening the structure. Perforations were made across the entire frame, reducing overall weight by 125 kg compared to the SSK. The combination of reduced weight and a power output of 300 hp gave the SSKL a power-to-weight advantage over any competitor of its era.
Rudolf Caracciola drove the SSKL to the 1931 German Grand Prix victory and the 1931 Mille Miglia — making him the first non-Italian winner of the Mille Miglia and the last for over two decades. Victories across the 1931 and 1932 seasons established the SSKL as the dominant force in European sports car racing before Mercedes-Benz switched focus to the new purpose-built Grand Prix cars.
The most celebrated individual SSKL was that of Manfred von Brauchitsch, fitted with a streamlined bodywork of aluminium sheets in place of the standard open-wheel roadster body. This aerodynamic enclosure enabled the car to reach 156 mph and allowed von Brauchitsch to win at the Avus race in May 1932. The Avus circuit, with its long parallel straights, was one of the few venues where aerodynamic advantage could be fully exploited. Radio commentators covering the event referred to the silver aluminium body as a "silver arrow," a description that would later be adopted to describe the entire Mercedes-Benz and Auto Union Grand Prix programme of the mid-to-late 1930s.
Only 33 SSKs were built across the production span of the S-Series, and only a limited subset of these were converted or produced as SSKL specification cars. Many SSKs were crashed during racing and subsequently cannibalised for parts. Approximately four or five entirely original SSK examples survive; their scarcity and competition heritage make them among the most sought-after pre-war automobiles. A 1929 SSK sold at Bonhams in Chichester in September 2004 for £4.17 million — the second most expensive automobile sold at auction at that time. A streamlined "Count Trossi" bodied SSK owned and restored by fashion designer Ralph Lauren won best of show at both the 1993 Pebble Beach Concours d'Elegance and the 2007 Concorso d'Eleganza Villa d'Este.
The SSKL sits at the intersection of two eras in Mercedes-Benz competition history. It was the final expression of the road-derived supercharged sports car formula that the company had pursued through the 1920s, and its Avus streamliner directly coined the "silver arrow" identity that defined the marque's greatest Grand Prix era. Rudolf Caracciola's 1931 Mille Miglia victory with the SSKL remains one of the most celebrated individual drives in pre-war motor racing.