Your car’s suspension stabilizer bar, or sway bar, connects the suspension to the chassis and reduces body roll. If you turn your car sharply to the right, you’ll feel the car (and you) lean to the left. The sway bar compensates for that momentum. The sway bar bushing is a piece of molded rubber or polyurethane that cushions the metal components of your suspension system and prevents them from rubbing against one another. If you feel vibration and/or hear excessive rubbing or squeaking when going over a pothole or bump, it might be time to replace your bushings. Performance poly bushings are often used for racing applications, or to lengthen the amount of life time between bushing replacement.