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. 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. 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.