The Tomei Exhaust manifold is made by "Lost Wax" production method with SUS304 alloy. For overall high performance we have designed the pipe diameter to be 41.5mm in diameter & 2.5mm in thickness which brings out the high quality sound. Highly accurate TIG welding, with smooth bends to decreases exhaust flow interference. The pipe angles were designed to increase exhaust flow efficiency. Attention to details with the smoothness of the internals of the product.