Subaru Impreza STI Brake Cooling Ducts 2008-2010STI Fitment Only The APR Brake Cooling Ducts are aerodynamically optimized to "funnel in" massive amounts of air. Also known as the venturi effect, when the vehicle speed increases, this funneled in air increases in both pressure and velocity as it passes from the larger frontal area into the smaller pipe section of the brake duct. When matched with appropriate high temperature air duct hoses (not included purchase hoses from your favorite racing