Car tuning is the modification of a car to optimise it for a different set of performance requirements from those it was originally designed to meet. Most commonly this is higher engine performance and dynamic handling characteristics but cars may also be altered to provide better fuel economy, or smoother response. The goal when tuning is the improvement of a vehicle's overall performance in response to the user's needs. Often, tuning is done at the expense of emissions performance, component reliability and occupant comfort. As a culture has grown around modified cars the term tuning has grown to encompass the cosmetic and stylistic changes owners make to personalize their vehicles. These changes can range from functional modifications designed to improve the performance or functionality of the car, to visual modifications which alter the aesthetics of the car and, in the case of certain mods, sometimes be detrimental to the performance or functionality of the car. Origin Since their invention, cars have always been subject to aftermarket modification. Both moderate and radical modification have been commemorated in the popular songs Hot Rod Race and Hot Rod Lincoln. The names of Abarth and Cooper appear on models styled after the cars they modified. With support from Ford, renowned engine manufacturer Cosworth went from modifying English Flathead engines for Lotus Sevens to dominating Formula One racing. In the 1970s and 1980s, many Japanese performance cars were never exported outside the Japanese domestic market. In the late 1980s and early 1990s, grey import vehicles of Japanese performance cars, such as the Nissan Skyline, began to be privately imported into Western Europe and North America. In the United States, this was in direct contrast to domestic car production around the same time, where there was a very small performance aftermarket for domestic compact and economy cars; the focus was instead on sports cars or muscle cars such as the Ford Mustang and Chevrolet Corvette. Because of their light weight and the increasing availability of inexpensive tuning equipment, tuned economy and compact cars exhibit high performance at a low cost in comparison to dedicated sports cars. As professional sporting and racing with such vehicles increased, so did recreational use of these vehicles. Many drivers would modify their vehicles in an attempt to emulate versions of racing vehicles. Areas of modification The essence of modification of a tuner car is an attempt at a significant performance increase—or