My guess would be that he modded the power amp to more like a Marshall, and modded the 1st gain stage as well. Of course I'm just guessing, but thats what he did with my Randalls.
Changed first gain stage as all modules must use the first gain stage that is built inside the Randall. Its less bassy, and helps when hitting the gain modules. It is switchable between modded and stock. Dave also reworked the power section so the presence control was more like a Marshall, and the depth control could be more usable. I can crank it up pretty good, and not have the amp all muddy or woofy sounding. I really think these mods should be standard on the amp, as it definitely sound better than they did stock. Then again, not everyone will agree.
BTW Jim, I think you'd dig the BE/C45 module with the saturation switch. I like it more than the HBE myself.