The Injen Downpipe is a full 3" catted downpipe made from 304 stainless steel. The bellmouth design allows for maximum flow for your Subaru with many mods and / or an aftermarket turbo. The built in high flow catalytic converter keeps it legal while still being efficient. Injen has incorporated a built in CEL fix which reduces the chances of throwing a code for your aftermarket downpipe. A second O2 bung on the top of the downpipe allows for easy installation of a wideband sensor. No gaskets are included but new hardware is provided.