The Invidia divorced wastegate downpipe for the Subaru WRX and STI has a plate the protrudes into the turbo exhaust housing to separate exhaust flow which reduces turbulence. The divorced type of downpipe housing is good for stock and smaller turbochargers; the protrusion does not work with some aftermarket turbos (i.e APS).The divorced Invidia downpipe is available with a high flow cat as well .
Part Number: HS05SW1DPC