leaning out at 10psi - no
cant boost skylines on std cooler - wrong
needs a fuel reg - wrong
its got to be something to do with ignition if you are in fact runnin 10psi. this means checking coil packs (done), spark plugs, and ignition module. however if the spark plugs are uneven in colour it may point to a blocked/clogged injector which isnt spraying enough fuel causing pinging, but youd hear that...
is it missing on idle and all the time, or only in high rpms? what gap have u got your plugs set to?