exhaust 2015 mustangBlowByRacing has recently confirmed the weight on the stock catback exhaust on the 2015 Ford Mustang, it weighs a hefty 71 pound 6 ounces. So if you replace your stock exhaust with aftermarket exhaust, you could save on weight and enhance your times at the track. Aftermarket exhaust way anywhere near 20 to 30 pounds lighter. Then you think if you change out the stock wheels for aftermarket wheels, as well as the battery, you might be able to get those 54 pounds back, a lot of Mustang fans are disappointed with the extra weight.