This EJ205 also has the AVCS choice to run for additional overall performance. To operate the AVCS, the avcs harness as well as the avcs ecu is needed. Even so, This really is optional, you don’t really have to run the avcs to help make the motor suit in the 2002 to 2005 WRX. This is a immediate long block substitute for 2002 to 2005 Subaru WRX.Y