Car tuning is modification of the performance or appearance of a vehicle. For actual "tuning" in the sense of automobiles or vehicles, see engine tuning. Most vehicles leave the factory set up for an average driver's expectations and conditions. Tuning, on the other hand, has become a way to personalize the characteristics of a vehicle to the owner's preference. Cars may be altered to provide better fuel economy, produce more power, or to provide better handling.
Car tuning is related to auto racing, although most performance cars never compete. Tuned cars are built for the pleasure of owning and driving. Exterior modifications include changing the aerodynamic characteristics of the vehicle via side skirts, front and rear bumpers, spoilers, splitters, air vents and light weight wheels.
Cars have always been subject to after-market modification. The golden age of car tuning was the decades between World War II and the beginning of air pollution restrictions. 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. Cosworth went, with support from Ford, from modifying English Ford Flathead engines for Lotus Sevens to dominating Formula One.