The main issue is that the octane of pump gas will limit you in your quest for 500whp on pump gas. Once ethanol comes into the mix it helps cool the cylinder and it is more knock resistant. The full race hpfp and Hondata 1530cc injectors are the combo with the most headroom for fuel with good...
I agree, I have seen depending on the commanded AFR that the limit seems to be around 410-430whp for the stock fuel system depending how hard you are pushing it.
One thing from my testing that has also shown an improvement is that the fuel system gains a bit of head room down low due to the...