Just because one guy wrote that about the PCM doesn't really mean I believe it 100%...... I'd prefer to build a Megasquirt system to have complete control over spark and advance, but then again we have integration issues with the factory stuff. I'll know more once I actually get this thing running and pick up an Innovate or get it on a rear wheel dyno and get a A/F graph. Maybe I'm just overly cautious because I have to pass emmisions. Keep in mind that it's the overlap that will cause issues on a computer controlled engine. Regardless of the compression, the computer will see more unburnt fuel at the O2 sensor at low speeds and it will try to lean it out.