Boomba Racing 220g Weighted Shift Knobs for the 2015+ Ford Mustang now available! Posted by admin on March 10, 2015 Posted in: Boomba Racing. Brass core for added weight and delrin shell for ‘temperature management’. Retains reverse lockout functionality! Posts navigation ← Boomba Racing License Plate Frames Now available! FREE Tshirt with every Subaru WRX/STI Throttle Body! →