You don't need a mini-afc to rescale the MAF. You can mod the MAF itself to rescale it by soldering on a resistor across the shortest bar and the middle long bar inside of it as shown the following picture. You can start with a 1.4k ohm, 1/2 watt value resistor and see how that works.
You will need to rework your entire MAF calibration table in the PCM tune if you do the resistor mod to the MAF, so keep that in mind.
Concerning spark blow-out, I was using Denso Iridium plugs and could only run about 13psi of boost with a 0.055" gap before experiencing spark blow-out. Dropped the gap to 0.040" and ran it up to 18 psi recently without having any problems. Other brands / cheaper grade plugs may produce different results vs. what gap you run them at.
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[This message has been edited by Darth Fiero (edited 06-11-2014).]