A complete exhaust system replaces everything downstream of the catalytic converter. Its main effect is sound: less restrictive mufflers, a more pronounced low tone, and a more immediate-sounding rise in engine speed. In terms of power, the gain exists but remains modest on a stock engine, because the main restriction in a production engine is further upstream - the catalytic converter and downpipe.

The second effect, less often highlighted but more long-lasting, concerns weight and durability. A stainless steel exhaust does not rust, can still be removed in ten years, and weighs less than the original aluminized steel exhaust. On a car you plan to keep, it is the part you only install once.