Duplex stainless steel exhaust system 1 × 100 mm for Audi A4 B6 Quattro sedan/Avant/convertible — TA Technix

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 sharper-sounding rise in revs. In terms of power, the gain does exist but remains modest on a stock engine, because the main restriction in a production engine is upstream - the catalytic converter and downpipe.

The second effect, less commonly marketed but more durable, is weight and durability. A stainless steel exhaust does not rust, can still be removed ten years from now, and weighs less than an original aluminized-steel exhaust. On a car you plan to keep, it is the part you only install once.