Apex'i GT Spec Cat-Back Exhaust System Lexus IS300 01+ Note: 60mm-65mm Piping Diameter 115 mm Tip size GT Spec Mufflers are our flagship line of exhaust systems. These race-bred exhaust systems were engineered to handle extremely high-horsepower applications. A'PEX is the only company in Japan to own and operate a 95mm (3.74 inch) mandrel pipe bender at this time. We proudly incorporate this 95mm piping on select applications to offer exhaust systems unmatched by any other manufacturer. Pipes for the GT Series are designed with minimal amount of bends and the canisters project at an angle like the N-1. The GT Series pipes and canisters are constructed of polished SUS 304 stainless steel. The 115mm polished tip give the GT Spec Mufflers an aggressive, yet refined style. All GT Spec Mufflers include the Super Silencer, which can reduce noise levels by up to 7 decibels. Engineered to Handle Extremely High-Horsepower Minimal Pipe Bends and Angled Muffler 115mm Polished Tip Give an Aggressive, Yet Refined Style Include Silencer to Lower Noise Levels Low Idle Rumble and Throaty Sound at Wide Open Throttle HP & Torque: 12-15 HP/15 ft lbs Torque Installation: Hangs from the same hanger locations as the factory exhaust and comes complete with all necessary hardware and instructions. Tech Notes: All GT Spec system include the Super Silencer, which can reduce noise levels by up to 7 decibels.