MadDad Street Series catted bellmouth downpipes use a purpose built 200 CPI metal substrate race catalytic converter offering increased flow over the standard 300 CPI units used in the majority of catted downpipes from most brands. This is a full 3" downpipe and ends with a standard 3" flange...no 2.5" tapers for factory donut gaskets which can rob you of up to 6hp on the typical STG II car. Make sure you choose a catback that also mates with a standard 3" flange...Maddad, Invidia and many others. FIts all 2008+ WRX and STi.
