The tuned pipe uses exhaust pressure waves to help the engine breathe. Its size and shape decide where in the rev range the engine makes its best power.

The manifold connects the engine to the pipe, and the pipe is the tuned resonator. Both lengths affect the powerband, so they are matched as a set.

Match it to your engine class and how you drive. A longer setup favours low-end torque, a shorter one favours top-end power.

Check the silicone coupler for splits and keep it tight with wire ties. A leaking coupler causes a lean, unreliable tune.