Is a popular hobby, in which a car is modified in order to improve its performance and handling and better suit the owner's driving style. As most cars leave the factory set up for average driver expectations and average conditions, tuning has become a way to personalize the characteristics of the vehicle to the owners preference. For example cars may be altered to provide better fuel economy, produce more power at high RPM or the ride comfort may be sacrificed to provide better handling. Car tuning is related to auto racing, although most performance cars never compete. Rather they are built for the pleasure of owning and driving such a vehicle. Another major facet of tuning includes performance modification to the car exterior. This includes changing the aerodynamic characteristics of the vehicle via side skirts, front and rear bumpers, adding spoilers, splitters, air vents and light weight wheels.