I didn't have to pay for the selin so that was free basicly how I look at it so the apexi neo was used and I got for a killer deal so I am gonna try and utilize both because it doesn't hurt to be able to fine tune the air fuel and see exactly what the selin is sending to the ecu by intercepting the signal to the neo right? Plus I don't have to run another wire to the neo since it's only gonna be getting one input from the selin and one output to the ecu. The neo came with the specific harness for the ecu so I don't have to splice any wires. The chips I have ordered always seem to run the car a little rich and unless I want to spend 500 to 1000 for a custom tune job on a dyno this seems like a legit alternative