A custom exhaust designed specifically for your car and your engine can improve things even more than a bolt-on kit.
Higher Quality Materials
Mild steel is fairly common in automobile production when it comes to exhaust components. It's fine, but it tends to deteriorate over time. This can lead to exhaust leaks and performance issues the longer you own the vehicle.
Higher-grade aftermarket exhausts like Holden Commodore VX VZ will often utilize aluminized steel or stainless steel for increased durability.
The Sound and the Feeling
There is simply a difference you will feel and hear when you have a better exhaust system. From the custom pipes to the muffler you select, you will clearly notice the added power when you drive.
As for sound, that's completely up to you. You can make the engine louder and more aggressive, which is what a lot of people want in an aftermarket exhaust. Or if you prefer, you can even install a top-quality muffler that makes it run a little quieter without sacrificing the horsepower gains. The possibilities are endless with a custom exhaust system!
Improved Fuel Economy
This can be a tricky subject when it comes to custom exhausts. The more efficient your exhaust system is, the more efficient your engine will run. This typically leads to better fuel mileage.
Many custom and kit exhausts are designed specifically with this in mind. Some will boost the torque and horsepower so much, however, that it has the opposite effect.
The engine has to burn more fuel to keep up with the increased power output. A good custom exhaust system can help you find the right balance between performance and fuel economy, but ultimately it's up to you.