The stock driveshaft on your 2015-2018 Mustang is heavy and isn't much of a match for the insane power levels your Pony is capable of, especially once you start stacking on power-adders and tuning. Aftermarket aluminum or carbon fiber driveshafts can handle huge levels of horsepower, torque, and speed so that you don't have to worry about snapping your Pony's driveshaft as you push it to the limit.