An ODB1 P73 ECU does not exist in the USDM, only ODB2, which isn't an option if OP wants to run s300 (without modifying the connections inside the ECU). JDM P73 ECU is ODB2 but will work similarly to ODB1. BUT, if OP is getting a new harness anyways, why would get get an ODB1 harness and then an...