It will make your engine perform better because you are not letting the engine breathe properly. By doing this, you will reach certain speeds that you couldn’t before. However, not all engines gain that much power, depending on what type of engine you have. Typically, smaller four-cylinder engines will gain more power than a larger V8 engine. That is because the more powerful the engine is, the less work it needs to do to beat any restrictions imposed by the exhaust. Also, if your vehicle has already been performance-tuned from the factory, you may not see as many improvements after installation.