Traditional design vacuum brake boosters consist of two heavy, stiff shells that must carry the high forces associated with applying the vehicle brakes. This paper shows how we developed a lighter booster with improved performance characteristics. The initial solution was to insert steel tie rods through the center of the booster and use thin guage steel shells. Whilst this reduced the weight, it did not provide the improved performance we were seeking. RP was chosen as a means of optimizing the design utilizing its low weight, high stiffness and suitability for molding in complex shapes. CAD and FEM was used extensively for design and several years material evaluation and testing took place before glass filled polyester was finally selected for production. The result is a RP booster that is over 50 percent lighter than traditional designs and provides improved application response.