IPD Plenums provide a simple, yet highly effective way to gain extra horsepower and torque for improved acceleration and quicker boost response. Featuring a new designed aluminum plenum which replaces the flat-walled stock plenum with a design that increases airflow and air speed (velocity) to the engine. Dyno tests on a 2004 Porsche 996 twin turbo revealed a 30 to 35 Horsepower increase at the rear wheels.