Whiteline BMW 1 Series (Exc M Series) & 3 Series (Exc M3) Rear 20mm SwaybarEngineered to 'Activate More Grip', sway bars are principally designed to reduce body roll or sway. By reducing body roll, lateral loads are spread more evenly across the tires thereby increasing cornering grip and improving outright performance. This Whiteline 20mm fixed position sway bar = more grip = better handling = outright performance it's the best dollar for dollar handling improvement you can make to your vehicle. In fact, benefits extend to