BBK 2.5 inch Off-Road X-Pipe for Ford Mustang 5.0L features 2.5 inch diameter CNC mandrel bent aluminized tubing. It has BBK's unique die stamped performance Xtracter center X section to ensure maximum flow and horsepower. It has OEM original O2 sensor locations and factory style die-stamped flanges which ensures a perfect fit. BBK In-house dyno-testing has shown solid gains of 15-20 horsepower depending on the application. All BBK full length X pipes are designed as direct bolt on to factory headers or any aftermarket shorty headers and BBK shorty headers for weekend track or race use.