The RS Evolution Muffler is a combination of an A'PEXi original patented megaphone piping structure design and larger piping diameters to produce ultimate performance for your turbo-charged engine.FUNCTION:- The ultimate performance at high RPM. - High effective exhaust by megaphone tube structure.- Hybrid silencer that creates of sound quality and durability.- The shell is made out of highest quality SUS304. - A'PEXi logo stamped exhaust tip.