oem nissan gaskets are super but not too sure the 500hp mark will be achieved reliably with a stock gasket..i kno from personal experience that 300 gives you no problems..i would recomend a mls gasket for a setup running on more than 14lbs..for studs regular arp's are good..if u wanna run a shit ton of boost L19's are the way to go

ka-t.org is gonna be the best source for ka info..do ur home work and teach ur self a few things!!!