Id run them as big as you can get away with without misfiring. Theres really no advantage to running a small gap if you dont need to (i.e. the ignition system cant fire it).

The only thing I can add is that at 32 psi boost, I had to gap my RN9YC plugs down to about 0.024" to get the stock 16V DIS system to reliably fire them.

 

NGK BPR7ES gapped @ .030" no problems running 20+psi with an MSD

^there 1 heat range colder than the RN9YC

 

Id run them as big as you can get away with without misfiring. Theres really no advantage to running a small gap if you dont need to (i.e. the ignition system cant fire it). .

what he said.
I have never used champion plugs because where I go they don't carry them so I use autolite 64's (65 stock and they never have 63 in stock) plugs .035 is good till 16psi and then .028 is good till 25psi on my car with stock wires or 8.5mm magnecore wires it didn't make any difference. I run .030 just because I don't venture above 20psi too often, I also change plugs every 2k miles. $4.50 is a small price to pay to keep the car running top shape.

 

I gapped mine to .025, 22 lbs boost. Buy you've got plenty of ignition so you can probably open the gap up. I say start at .025 and keep opening until you detect a misfire.
Guy Douglas