Originally Posted by
10_SS
not that it matters here, but I build a breakout PCM connecter harness that lets me interface a MS3X piggyback on my 2010 E38 Camaro to control fueling, I leave the spark to the stock ECU since it is better with knock sensors, but this way you can also tie in to all sensors and trigger things much easier and better like fans, PWM fuel pumps, Alchohol, blow off valves, etc.
It goes between the stock ECU plugs and the stock ECU so if something happens just unplug the piggyback section and plug back in the stock harness.