Well sounds like your engine was not tuned on the dyno for the third reason I could be wrong. I have the same mods you do maybe a little more and run 17psi on pump gas. I beat the shit out of my car all the time and have been for A year and a half. But of course all cars are different etc etc. But if I were you I would just do option number 3 if you are going to just stick with the sp 500's get an oil cooler and an intercooler also please get it tuned if you haven't already and gauges never hurt anyone maybe even a wideband.