HKS SUPER TURBO EXHAUST SYSTEM FOR 93+ MAZDA RX-7. THE SUPER TURBO MUFFLER IS A FULL EXHAUST SYSTEM SPECIFICALLY DESIGNED FOR TURBO CHARGED VEHICLES. BY IMPLEMENTING AN 75MM STRAIGHT PIPE WITH MINIMAL BENDS, THE SUPER TURBO MUFFLER PROVIDES HIGH EXHAUST FLOW AND EFFICIENCY AS WELL AS GREATER HORSEPO..