2015-23 Mustang GT header system designed to maximize the horsepower on 5 liter motor. Don't settle when it comes to your Mustang and get the best header system on the market. Our products have a reputation for unmatched quality and performance. Do yourself a solid and get a set ordered today so you can gap your buddies on the track. Features: M24HCAT Add horsepower and torque with this bolt-on upgrade 304 Stainless construction will last a lifetime Smooth mandrel bends optimize exhaust flow Fully TIG welded for strength and beauty Stock Exhaust (Factory Connect) 1-7/8" for Naturally Aspirated Built To Order in 4 Weeks Emissions: This product is not legal for street use on an emissions-controlled vehicle. It may be used on dedicated competition or pre-pollution controlled vehicles only.