Lancia is renowned in the automotive world for introducing cars with numerous innovations. These include the Theta of 1913, which was the first European production car to feature a complete electrical system as standard equipment. Lancia's first car adopting a monocoque chassis – the Lambda produced from 1922 to 1931 - featured 'Sliding Pillar' independent front suspension that incorporated the spring and hydraulic damper into a single unit (a feature that would be employed in subsequent Lancias, up to the Appia that was replaced in 1963). In 1948, the first 5-speed gearbox was fitted to a production car (Series 3 Ardea). Lancia premiered the first full-production V6 engine, in the 1950 Aurelia, after earlier industry-leading experiments with V8 and V12 engine configurations. It was also the first manufacturer to produce a V4 engine. Other innovations involved the use of independent suspension in production cars (in an era where live axles were common practice for both the front and rear axles of a car), and rear transaxles, which were first fitted to the Aurelia and Flaminia range. This drive for innovation, constant quest for excellence, fixation of quality, complex construction processes and antiquated production machinery meant that all cars essentially had to be hand-made. With little commonality between the various models, the cost of production continued to rise, while flat demand eventually affected Lancia's viability.