Ok, after talking to Leo (at least I think it was Leo; SN Password JDM on HT), this is the gist of it: The Power Getter is more of a top-end exhaust, wild the RM01A provides power both in the top-end and mid-range. As far as design goes, he also said the RM's MORE straight-through design was better (which is, I'm guessing, what's responsible for the wider powerband improvement). So I suppose until someone feels like throwing some money away and dyno testing the PG, that's as good of a comparison as we're gonna get.