BBK Performance X pipes have been the number one performance brand that Ford Mustang enthusiasts have enjoyed for years. All BBK 86-08 Mustang direct replacement X-pipes feature 2.5” diameter CNC mandrel bent aluminized tubing with two 50 state legal - high flow catalytic converters and BBK's unique die stamped performance Xtracter center X section to ensure maximum flow and horsepower. OEM- original O2 Sensor locations and factory style die-stamped flanges ensure a perfect fit and BBK In-house dyno-testing has shown solid gains of 12-20 horsepower depending on application. ALL BBK full length X pipes are designed as direct bolt on to factory headers or any aftermarket shorty headers as well as of course BBK shorty headers. Each BBK X pipe offers performance, quality and value that guarantees years of top performance for your Ford Mustang. New applications are being updated to the ever growing BBK Performance product line if you do not see your application please e mail us for availability. Please Note: *Part Number 1770 is made from 2-3/4" Tubing for built engines and high performance applications