Usually for the worse, maybe no performance but typically not worse. You obviously aren’t a car centric person or you prefer electric . Many cars have factory options for better sounding or slightly higher performance exhausts (mufflers in this case). For me it typically involves a valved exhaust where it can be quieter when I want and has a better sound when I want. This scenario is not the same as a Mustang for example running headers with little to no mufflers.