This range of high performance exhaust systems from HKS has been carefully designed to improve flow rate and reduce back pressure whilst retaining road legal noise levels while maximizing high end power gains.The HKS Hi Power range of exhaust consist of different exhaust systems that all offer their own benefits depending on your needs.Silent Hi Power exhausts offer high performance and a sporty appearance with the added benefit of reduced noise levels, these systems are made of T304 grade stainless steel for high lustre and long lasting performance. They also introduced the silent chamber on certain models which removes alot of the lower frequency noise.Hi Power 409 exhausts are a cost effective option, The rear section is made from SUS304 grade stainless steel while the non visible piping section is made from coated T409 which is more resistant to thermal expansion and has improved acoustic properties. This allows Hi Power 409 systems to have a straight through design without fear of