TEGIWA Race Exhaust Manifold. Changing the manifold is one of the best modifications you can do to your K-swapped Honda. Just with this alone, gains of between 5-10bhp are achievable before mapping. With supporting mods and mapping, gains of between 7-15bhp and a lot more torque are easily achieved. Constructed from premium 304 grade stainless steel the header features the popular 4-2-1 design, CNC mill-cut flanges, and robotic rotation purge TIG welding. Being a 4-2-1 configuration means it gives both excellent mid range and peak gains. It has been proven as being one of the best 'off the shelf' headers available. Installing this header removes your cat. Including new gaskets and spring bolts.