Invidia WRX/STi Polished Divorced Waste Gate Downpipe. Invidia offers both catted and catless divorced style downpipes that are designed with a separator plate between the turbine and wastegate exhaust streams. Divorced style downpipes reduce exhaust turbulence for exceptional exhaust flow and performance. Every Invidia downpipe features 3in diameter stainless steel piping, 1/2in thick flanges, and a cast upper mouth section. Please note that without engine management such as the Cobb Accessport, a catless downpipe will trigger a check engine light.