if you up the boost at all then i would recommend going to heat range 6 plugs. as for the gap, that really comes down to the strength of the coilpacks. if they are still in good condition then you could get away with the 1.1mm gap.
also next time you get plugs i wouldn't bother getting platinums or iridiums. i'd just go the cheap coppers. doesn't work out to be any more expensive in the long run, just change them every 10 or 15,000kms. in a stock setup you'd probably get nearly 20,000kms out of them.