to get stuff done, probly RMP. i allso had the same question as that but it realy comes down to what you are going to do with your car. i am going to turbo the m20. its a farly inexpensive way to get alot of power in a m20. and if your not into tuning it yourself and going standalone, i think it was markD or someone that makes a chip or the m20 that will run with 7 psi.
hope that helps. good luck