If you are using a megasquirt, all you need factory connectors for are the cam/crank sensors, and the coils. Everything else is fairly universal/GM style. I cut up a factory harness and made my own reusing whatever I could, but ran new circuits for TPS, IAC, IAT, MAP, and Coolant. I used an analog sensor for MAP because I didn't want to run a vacuum line inside the car for the on board map. Instead, I use that one as a barometer sensor. I also added analog sensors for oil and fuel psi. I'm not using knock sensors.