Ok yeah that video serves as a starting point.
From that video I got enough to research the rest. The problem is that for some reason they are marketing this all wrong, they are presenting it as a product that will improve combustion efficiency instead of what it is (mostly) a lubricant. Since about 80% of the energy contained in fuels is usually wasted as heat, 5% in transmission and only about 15% of the energy in a gallon of gas makes it`s way to the tires (where it`s put to good use), adding a better lubricant to the engine will decrease heat waste and improve consumption. It is possible that it too improves combustion in some engines but that is not the main reason why this product should work, in fact, on that video they clearly state at the end that the product is non volatile and non flammable almost the antithesis of what a better fuel is supposed to be.
Knowing that it is the esters in it lead me to this page http://www.ethosnw.com/ester.html for a more detailed explanation of how esters work http://en.wikipedia.org/wiki/Esters I would suggest you include a combination of those two or at least link to them so that people know that they are buying a lubricant not a fuel additive. Why on earth would they market in this manner I don`t know.
From what you`ve said and what it is I would surmise that given that it is a lubricant not an additive it will likely work better on new engines, as it`s compression is almost perfect. As the engine ages it loses compression (less energy wasted as heat, more energy wasted as unburned fuel) so Ethos becomes less and less effective as the engines age.
Interesting, IMO it would be a good idea to verify that this is the case and then clearly state so on your web site so that people with older vehicles do not buy it. Because naturally, when they don`t get the expected results they would assume that the product is a scam.





