Whiteline '08-'14 Subaru WRX STi Heavy Duty Adj Rear 22mm Sway BarRear 22mm Swaybar X Heavy Duty Adjustable As the name suggests their objective is to reduce sway, or body roll, and stabilize a vehicle under lateral (cornering) forces. Formula 1 cars still use sway bars along side the shocks and springs as it is the ONLY suspension component principally designed to control body roll. Unfortunately, many aftermarket spring manufacturers still design their lowered springs too hard, trying to control body roll when its