Carbon fiber A-pillar fairings are designed to provide a smooth transition from the front  windshield frame to the frontal facing rain gutter.  Significantly reducing aerodynamic  drag at higher speeds because the rain gutter (without fairings) creates a major point of  air flow turbulence.  These have been proven to increase top speeds by 5-6 MPH and  were historically used by 935's as well as the Ruf CTR and BTR.  More current  applications include club racers, enthusiasts, and those who appreciate every advantage.