Genuine Subaru Trunk Spoiler WRX GVB (2010-2014 Sedan)This Trunk Spoiler is the same shape as the part used on the STI complete car "WRX STI tS". It is an aerodynamic part that improves rear tire traction by using the flow of air across the body while driving to apply down force. Geometry that has been shown to achieve the best performance during repeated wind tunnel testing of actual cars provides an optimal balance of air resistance (Cd), front to rear aerodynamic lift (Clf Clr), and down force to