The Spoon product, the N1 muffler, has sufficient specs, so they actually tested it at the race to see how the sound would affect the driver in a long race. After the race, the drivers gave high marks such as that the volume was moderate enough to prevent fatigue, and that the sound quality was good enough to drive comfortably.
This N1 muffler kit for FL5 was developed using the experience gained there. The pipe diameter and silencer position were laid out based on flow bench simulation data, and optimized through repeated tests on actual vehicles.
In anticipation of boost up, matching with upgraded turbo, and use in racing, the front pipe and main pipe diameters are set to 70mm, and the tail part adopts a 80mm end pipe with a 145mm cannonball type silencer.
Front/Main pipe diameter: 70mm
Tail: Bullet-shaped silencer: 145mm end pipe 80mm dual exhaust tip