This product has been developed in response to considerable demands for a balance between peak power and torque. In its development, Spoon has implemented all possible combinations of pipe diameter, assembly rotation, and other similar factors in exhaustive engine-bench, flow-bench, and actual driving tests. Furthermore, without any reduction in low speed torque, the discharge of gas was carried out forcibly from the exhaust port in the high speed range, and the results of this showed that it has also been possible to achieve increased replenishment efficiency for the combustion chambers. This header is primarily designed for B16A engines. This header will also bolt up to your factory catalytic converter. No special flange or gasket is needed.