When I am driving at WOT the car seems to be hesitating almost like a misfire or maybe a knock but from the data logs I can see that it is not knocking. This usually happens after the car is heated up a little after a few pulls and only does it when under boost. Sometime it will even do it under 5 or 6 psi.

The kit is a mix between an line pro stage 1 and a few other parts with a turbonetics turbo.
Walbro 255 fuelpump
rc 750cc injectors
hondata 4 bar map sensor
AEM ems v2
and a aem wideband that I use for the O2 feeback.
I bought the kit which was tune on an AP2 with a 3mm headgasket and since then have been adjusting the tune to suit my AP1. The AFR's look spot on, about 11.5 under full boost and I have the ignition set to around 12 degrees at 12 psi on 91 octane pump gas which is some what conservative compared to some other S2000's I have seen.

I cant figure out why the car is sputtering. Before I was running a 7 psi waste gate spring and the car had zero issues, as soon as I bumped it up I've been having these sputtering issues that almost sound like a knock but I am not seeing much higher than 1 volt when data logging as far as knock. I thought the spark was blowing out so I bout new NGK copper plugs gaped at .029 and the problem persists. At times it also seems as if it hits a small rev limiter like the AEM pulls out all the timing but I don't see why it would do that. Other than that the car runs perfectly fine out of boost and city driving is spot on. I have tried lower and raising the ignition timing to see if that helps and so far the problem is exactly the same.

More information: The car has a log manifold, vtec comes on at 6k, no cat or mufflers just a resonator, live in California with 91 octane, and stock engine. Thanks for all the help.