Replacing the standard Up-Pipe with our high performance decat Up-Pipe will improve your Impreza's exhaust gas flow dramatically due to the removal of the restrictive catalytic converter, resulting in increased power output ,improved throttle response and reduced turbo lag. Features: Manufactured from mandrel bent T304 stainless steel TIG welded 2.5" bore with 12m thick flanges Includes flexi joint to allow for expansion of the manifold