IS Series Short Ram Polished Intake System (IS1890P) by Injen. HP Gain: +12.6 hp. Includes: X-1018 Filter. The IS Series is a traditional, underhood air intake system that takes the place of your factory airbox and air filter, and the factory air intake tube. The EA Nanofiber air filter allows increased airflow and the aluminum alloy intake tube smoothes the airflow path into the engine. The increased airflow and velocity results in more power, increased acceleration and better fuel economy.