This 24mm Adjustable Rear Swaybar was designed by Whiteline specifically for the Subaru Impreza WRX STi. The 2004-2006 Subaru WRX STi came factory-equipped with a 20mm rear swaybar, while the 2007 model received a 19mm rear swaybar, offering a 107% and 155% increase in stiffness, respectively.