OEM TT Exhaust system

Precat - passenger side - with O2 sensor connected

Precat - looking inside

Specialty Z downpipes - downpipes are the aftermarket option for precats

Downpipes with associated hardware

Catalytic converters

O2 Sensor

Exhaust manifold on an N/A, passenger's side -
O2 sensors on an N/A are in the manifold - no precats