I'm sure Wren will chime in on this. Most "octane boosters" only boost your octane by .1 that is point one. I can not say that is true for all of them, but it has been my understanding that sums it up for most.
I think the best solution, if you want more octane, is to add toluene to your fuel. You need a spreadsheet so that you keep the mixture the same. I don't know who all uses it, but if I recall, Wren does.
As said above, octane does not boost horsepower. Octane is simply a rating for how difficult it is to ignite the fuel. The higher the octane, the harder it is to ignite.
I'm sure if I have any of that screwed up, I'll be corrected.
*edit* To read between the lines on that website, perhaps someone should send an e-mail asking how much 93 octane pump gasoline was used in conjunction with this product they are marketing to achieve 100 octane. Additionally, questions regarding current formulation are called into play. The little asterisk would make me think they produced some honestly effective stuff at one time, and probably reformulated it to reduce the cost and effectiveness to rake in the cash. That'* just my opinion/thoughts/concerns.
Maybe it'* just me, but I don't trust anyone selling anything that I can't measure the improvements on myself.