Lol, I think you misread that description. That description would only be valid for co-location as well, which probably isn't what you would do with two. And it wouldn't hold when pushing these subs to their limits as well, where they will only give you 2x as much output. So no, buying two will not give you the potential output of four. However, buying two can bring down the distortion characteristics much more disproportionately than having a single sub. There are other good reasons to get multiple subs setups as well, such as better frequency response throughout the room, and much reduced localization.