Many cars, from drag racers, to sports cars, to monster trucks carry different kind of spoilers on them. Cars have spoilers to increase their grip on the road. Normally the weight of a car is the only thing that forces the tires down onto the pavement. Without spoilers, the only way to increase the grip would be to increase the weight, or to change the compound the tire was made out of. The only problem with increasing the weight is that it does not help in turns, where you really want to grip. All the extra weight is inertia, which you have to overcome to turn, so increasing the weight does not help at all. The way the spoiler works is like an airplane wing, but upside down. The spoiler actually generates what's called "down force" on the body of the car. One major advantage of this can be seen very readily. Instead of having a heavy car, which is slow, or having a very light car, which can slide away easily, you now have a car that sticks better the faster it goes. It's important when replacing a spoiler, that you purchase the right spoiler to ensure it is compatible with the make, model and year of your car so that it not only fits your car correctly but also blends in with the design and appearance of your car.