no - engine wiring harnesses are not interchangeable - the DX chassis harness which comes from the ECU to the firewall does not have the necessary wires in it for the other 2 fuel injectors or the 2 wires for the Cylinder Sensor - these are the wires that are added from the ECU directly to the engine bay when you convert the DX engine harness from DPFI to MPFI - the DX chassis harness on the passenger side has 2 connectors where the engine harness plugs in - the Si engine harness has 3 connectors at that location - you could swap the entire Si harness (engine, chassis, everything) into the DX and make it work, but that is a ton more work than just converting the DX engine harness