Stainless steel exhaust system 2 × 80 mm for Audi A3 Quattro/S3 1.8/2.0TFSI type 8P — TA Technix

A complete exhaust system replaces everything after the catalytic converter. Its main effect is sound: less restrictive mufflers, a deeper tone, and a more pronounced rise in revs to the ear. In terms of power, the gain exists but remains modest on a stock engine, because the restriction in a standard engine is mainly upstream - at the catalytic converter and downpipe.

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