I got mine done by the same people mate, havent installed them or run them yet so comment on how well they work
the way i saw it was
1. I can either go to the trouble to sell my standard ones, buy second hand z32 ones, screw around with plugs etc
2. Buy genuine nismo ones that are more then $1000 dollars as a pair from memory
Or 3 get them cleaned recalibrated and have them still looking stock and able to bolt straight back up to my apexi intake system... remember though ull need to pay for postage to send your standard ones off and get them sent back
cheers