An utterly iconic shape that some say defined the shape of 1930's sports cars, the Mercedes-Benz 540K was equally well equipped to fend off any of its European rivals when it landed, boasting a 106mph top speed that few cars at the time came close to. The 540K also delivered startling acceleration and exceptional handling and was one of the earliest road going vehicles to use the180hp, 5.4-liter supercharged straight eight-cylinder engine.

This particular model represents one of only six 540K Sport Cabriolet models, distinguished by an exceptionally low windshield and long open wings. Its definitive style was set by Mercedes-Benz in-house coachworks known simply as Sindelfingen, with its grand front end featuring a V-shaped grille moved back from the bumper and bracketed by trumpet horns and spotlights. Twin exhaust pipes project from the side of the hood and the cockpit is set back almost at the rear wheels. The car has passed through various hands and benefitted from numerous restorations.

These include a no-expense-spared, two-year 100-point restoration, which included completely disassembling and stripping the car, before methodically rebuilding and restoring every part. The exterior is finished in flawless black with claret accents and matching black cloth top, while the interior was done in black leather with contrasting red piping. A mother-of-pearl center dash boasts ivory gauge faces and switches surrounded by polished wood. The 540K has won various concours competition awards, while veteran experts decreed the car retains the correct engine, original transmission and body.

RM Auctions has put a €2 - €2.4 million estimate on this masterpiece of 1930's style and engineering, which will go under the hammer on 12 May at the Monaco Auction.