Looking for a few extra HP and quicker turbo spool from your EVO? Look no further then the Authority stainless EVO high flow o2 housing. The Authority high flow o2 housing replaces the restrictive stock pipe in between the turbo and the downpipe. After installation you will notice quicker throttle response and improved turbo spool. We suggest running this part with a 3" downpipe for optimal gains. The Authority EVO high flow o2 housing will work with most aftermarket downpipes such as Apexi, Authority, HKS, Helix, RMR, or turbo xs. This high flow o2 housing has a threaded bung for the stock o2 sensor to easily plug into.Fits: Mitsubishi Lancer Evolution VIII 03-05