Most cars come from the factory with at least front anti–sway bars. Anti-sway bars are designed to limit the amount of sway, or roll induced into the body of your car during radical maneuvering. This is accomplished through torsional stresses induced into the sway bar by the forces the car undergoes during cornering. The thicker the sway bar you have in your car, the better your car is going to feel when driving at high speeds. Some cars don’t come from the factory equipped with rear sway bars. Installing a sway bar on the rear of your car will greatly enhance the high speed-handling characteristics.