The RoadsterSport 4 stainless steel exhaust; a revolution in exhaust technology finally available for all 1999 through 2005 Mx5s. Now you can have great performance with a mild sound thanks tothenewly included"Helmholtz chamber". Built from T-304 polished stainless steel, this exhaust features an exclusive Helmholtz chamber that massively reduces the standing wave 'boominess' inside the exhaust system! Cuts the 'booming' frequencies of 120-130hz by over 40+db inside a top up Mx5 cabin. This system includes removable baffles that you canuse to control the final sound level. Includes mounting hardware and gasket, as well as a lifetime warranty from the manufacturer.