Koenig-Specials—otherwise known simply as “Koenig”—is a German tuning house founded in 1977 by German publishing tycoon-turned-racer Willy Köenig. The company rose to fame in the 1980s and 1990s modifying Ferrari, Mercedes-Benz, and Porsche vehicles. The road-going machines that wore the badge were known for their enhanced performance and outlandish body kits. At the 1981 Internationale Automobil-Ausstellung—or Frankfurt Motor Show—Mercedes-Benz introduced the C126, a two-door coupé version of the W126 saloon. The C126 560 SEC, upon which this car is based, followed in 1986 and was powered by the 5.5-litre V-8 M117 engine. Rated to produce 268 bhp, it was the most powerful engine fitted to any C126 class Mercedes-Benz.

This 560 SEC rolled off the Sindelfingen production line in June 1990. A well-specified example, it left the Mercedes-Benz factory finished in Blue-Black Metallic, over a Black leather interior, with perforated leather on the front seats. It was optioned with front heated seats, on-board computer, Acceleration Skid Control, and automatic climate control. As this car was destined for Japan, it also included a fire extinguisher, which was a safety requirement for that market.

Upon being sent to Koenig-Specials, the car received the “Version II” body kit and the rare Albrex supercharger for the 560 SEC. This supercharger increases the power output from 268 bhp to 400 bhp. This example features front, rear, and side skirts, widened front and rear fenders, as well as a rear spoiler lip. Additionally, Koenig fitted a set of staggered 17-inch OZ Racing split-rims with silver-painted spokes and polished alloy dish. The wheels are now wrapped in Pirelli P-Zero tyres.

On 6 March 2014, this 560 SEC was imported into the United Kingdom from Japan and registered for the road in April 2014. On 24 April 2014, Mercedes-Benz specialist John Haynes Auto Technics repaired the Albrex supercharger and fitted a new belt, at a cost of £1,646.35. Presented with this vehicle are invoices for work carried out from 2014 to 2021, including installing new tyres, shock absorbers, and two front control-arm bushings in the summer of 2020.

On 27 May 2021, this 560 SEC received a 12,000-mile service and inspection. The engine oil and filter were changed, braking system inspected, and fresh fluid added. The air conditioning circuit was checked for leaks and re-gassed, and new spark plugs and alternator belt were fitted. On 20 July 2021, a new radiator and fan blades were installed, as was a new power steering belt. The odometer shows 91,275 kilometres at the time of cataloguing.