BBK Performance X pipes have been the number one performance brand Ford Mustang enthusiasts have enjoyed for years. They are available as a full length pipe to fit shorty headers or as a short mid pipe to fit BBK full length headers. These BBK X pipes are available with hi Flow catalytic convertors* for street use or as OFF ROAD ONLY * race versions. ALL BBK X-pipes are 2.5" diameter CNC mandrel bent aluminized tubing and feature BBK's unique die stamped performance Xtracter center X pipe section to ensure maximum flow and horsepower. 2005 & up X-pipes are made from 2-3/4" Tubing and feature a merged X to maximize the high reving free flow potential of modern V8 engines. OEM-Original O2 sensor locations and factory style die-stamped flanges ensure a perfect fit. In-house dyno-testing has shown solid gains of 15-20 horsepower depending on applications. ALL BBK full length X pipes are designed as direct bolt on to factory headers or any aftermarket shorty headers including of course BBK shorty headers. BBK Short Mid pipe are designed to fit ALL BBK Full length headers only. Each BBK X pipe offers performance, quality and value that guarantees years of top performance for your car.*(not street legal - high flow convertor pipes are not legal for sale in California as of Jan 2009) new application for California wil be available soon-call for more information.