 Later, investment in developing racecars for motorsports produced returns through sales generated by the association of the name of the automobile with the winners.Unique race vehicles were built at the time such as the first mid-engine and aerodynamically designed, "Tropfenwagen", a "teardrop" body introduced at the 1923 European Grand Prix at Monza.In the last production year of the "Benz Sons" company, 1923, three hundred and fifty units were built.