There are a number of design requirements when creating an exhaust system for a vehicle. Modern systems are centered around increasing performance, lowering emissions, and reducing noise. Noise is controlled by designing baffles and resonators which are able to cancel out certain noise frequencies.

The noise from each cylinder firing event can be controlled and timed to reflect back against each other, pass through padding which can absorb some noise and also resonate to provide an acceptable sound. Performance Exhaust systems are therefore something that can not be easily designed. There are always compromises somewhere, with the first to go usually being the silencing effect. If you are looking at buying a new performance system, you should look out for changes to the design that would be beneficial. For example, updated equal-length exhaust manifold primary pipes, or repositioned X sections on “V” engine exhausts. Larger diameter pipes may change the sound, but it is often unlikely you will notice any improvements to the power. Likewise, Stainless steel exhaust manifolds that follow the design of the original will not provide any improvements as they will not fundamentally change the exhaust tuning.