The spoiler is designed to redirect airflow for better aerodynamic performance of the vehicle. And this affects the behavior of the car on the track. In addition, the spoiler can give the car an entirely different look, make it a little more sporty and aggressive. If you want such tuning for your car - look on amazon, there are many different spoilers available. There are those that are attached to the rear window, and there are for the trunk lid. A large selection for different makes and models of cars.