Hold on, the way I read that he had the fake cat sensors before AND after the resonator, as in, had fake cats in place of the O2s you actually NEED to be in the hear and in the ehxuast stream...
I think he has long tube headers with upstream O2 sensors, then resonators(fake cats?), then downstream O2 sensors...
The non fouler trick in the downstream sensors should have done the trick for him. I think it didn't work, then he added steel wool in the non fouler and it worked.