Sway bars are really anti-roll bars. Their primary function is to minimize body lean; therefore; increasing the car's handling capabilities. In effect, sway bars are sort of a torsion bar. They work by stiffening the chassis to resist body roll. What size bars are best for your Z? That depends on how and where you'll be using the car. For most street driven vehicles, you need to strike a good balance between performance potential and ride quality. Contrary to some stories you may hear, large sway bars will adversely affect your car's ride. Remember that sway bars are a chassis stiffener. Consider how hard you drive and the condition of your local roads. Our Motorsport sway bars are sized to make your Z handle better while retaining a ride quality similar to the stock suspension. Our sway bars are manufactured from automotive grade spring steel. Since sway bars are torsion bars (a form of springs), regular steel will not do in this application. The sway bar uses end link mounts that are forged. Welded on end link mounts are prone to failure. Developed to our specifications, these sway bars substantially reduce body roll and increase cornering force. Manufactured to the highest quality specifications using: Automotive-grade spring steel for long life, better fit, and best function. Made with forged ends. Includes urethane bushings. Plated installation hardware. For best handling characteristics, our bars were designed for installation as a set (front and rear). Sold only in pairs as a complete kit. Front bar = 1" Rear bar = 7/8"