AEM's Series 2 EMS is a complete engine control system that plugs into the factory harness and uses the factory sensors. This means you do not need to replace any parts of the harness or sensors, just plug the EMS into the harness and begin tuning! The Series 2 EMS allows you to control every aspect of your SR20. From rev limit, timing, adding different sized injectors, boost control, nitrous injection, even anti-lag and individual cylinder fuel and timing trims, the Series 2 EMS gives you total control from an easy to use interface. fits S13 SR20DET only