The ETS Mitsubishi Evo 8 and 9 Air Filter Kit is a great way to economically replace the stock air box with an open element filter to maximize airflow. Our Evolution IX and IIIV kit feature a genuine K&N air filter and a contoured 4.5″ filter inlet velocity stack adapter for smooth flow into the factory MAF. These pieces will bolt directly in place of the factory airbox for a quick and painless installation.