As many people know, building and designing your car by yourself can be hours of “exhausting” work. The research and experience required to build a vehicle should not be taken lightly. Making an exhaust that sounds good, flows smoothly, and is on the quieter side is far from easy.
A common myth is that custom exhausts are cheaper than bolt-ons. This is untrue in the vast majority of cases. Having a shop replace the stock mufflers with 2 cheap low grade “custom” mufflers and then performing a welding job may sound nice, but you shouldn't expect any performance gains.
Horsepower and torque are often lacking when you buy a new vehicle off the car lot. By adding your own aftermarket performance exhaust system, you can gain back some of that power in your engine. Your engine will be able to breathe a lot better, and all the extra gas that gets to escape through the new exhaust path makes for a more powerful experience.
The better aftermarket exhaust systems around today make for a slightly louder experience than your stock exhaust when idling. When the driver accelerates, the deep and low “growl” can be distinctly recognized as more powerful than your average system. The smallest tweak can sometimes make all the difference when it comes to performance issues.
Crush bend pipes are usually standard with a decreased diameter which slows the way air flows.
Mandrel bends are pipes that are smooth and remain constant in diameter through the whole bend. There's less resistance which means more efficiency and better performance.
Average factory exhausts come made from mild steel which tends to deteriorate over time. You can improve the longevity of your system with a little research. Thinking about how you use your vehicle will help you make the best choice.