dude, im not saying your wrong or right etc.... i just want to clarify the rb20 that they have built was a lazy engine that was replaced my a fresh one out of a customers car, which had been laying around, they put it in an s14 shell, used a whole heap of parts laying around and FOR A LAUGH tried to find the limits of the motor, It was over a few beers, a few mates and a few laughs after hours and im pretty sure they intended to blow it up, It was by no means an example of what they'd deliver to a customer in any way...
do a search man, i personally wouldn't run any more than 17-18psi which a thicker headgasket.