The Pro Circuit Ti-4 GP system is designed as a total performance exhaust system. This exhaust system is dyno and track tested by riders like James Stewart, Ricky Carmichael and Ryan Villopoto as a no-compromise full-race exhaust. The ultra-lightweight titanium Ti-4 GP is Pro Circuit's premium exhaust system and it includes their titanium header pipe. The Ti-4 GP exhaust will boost performance from bottom all the way to the top end, making it easier to ride and lowering lap times. The silencer can is easily repacked simply by removing the inlet cap screws and re-wrapping the silencer core. The Ti-4 GP meets all AMA sound restrictions. This is the exact same exhaust system that won four out of five AMA National and Supercross titles in 2007.