The only reason why Forrestang and ATL, the only two people in the 300+ whp club right now, are only running around 315 wheel is because they ran out of fuel. Had they been able to turn up the boost or timing then I am sure they would have, however they both said that they leaned out at 310 whp. I am not sure what you mean by saying "the fuel system is not good to make more than about 315 whp, no matter if its rich lean W/E". It does matter, if you are still running pig rich at 315 whp then you still have fuel to work with, which was not the case with the 300whp people.
what i meant is that no matter if you are rich at 21 psi or lean at 21 psi! not at 315whp! sorry(freak)