Man, that post was so long it was painful! Bottom line is you've never actually used the product TT, but you're pretty sure it's no good? Ha ha, no worries mate, that's gotta be more credible than Shell's offical website. 
It took far longer to write it than read it. And, I'm glad my minions have finally arrived in Oz to hold your eye lids open facing the computer screen so you can read every last letter I type! There is just no substitute for brute force, eh? Oh, wait, there is reason and understanding... Anyway, I've spent half a lifetime reading, understanding, facts and figures about materials and devices and applying them to practical applications. There are facts, there are relevant facts, and there are supportable facts. All these pale in significance to "feelings", according to some people. I forget who said that. Was it Oprah, Rosie O'Donnel, Barbra Striesand, Hillary Clinton, or Diane Fienstien? Perhaps a chorus line of them all in row? Pretty credible sources don't you think? Dang, where's that emoticon for puking?
But, I digress...
No, I haven't used the product of your particular religious affiliation. But, here in the states we have access to three grades of gasoline, regular, premium, and in between, (names vary between vendors to further confuse the consumer). These are all based on RON numbers which is an anti-knock rating NOT directly related to it's energy content. In fact, some states implement Gasahol during parts of the year, which has exactly the same RON number ( or rather the average of RON and MON as is standard in the states). But, it has decidedly and measureably less energy content. It most definately reduces your fuel mileage because less "work" can be accomplished per unit measure. It leans everyone's mixture because there are less hydrocarbons per unit available to combine with the same volume of air entering the engine. If one was running too rich before, simply adding Gasahol can IMPROVE the engine's power output!
I never said your recommended fuel is no good. I'm sure it is fine for it's intended application. I just can't find scientific justification for a performance boost in a stock Honda SOHC4 properly tuned. Though, there might be some if you advance the timing a bit. But, you said the fuel worked better simply by it's introduction, and I wondered why? The web site you offered doesn't answer that question in any quantifiable, measureable, or substantive way. Which, I believe, is intentional on their part. Verifiable Dyno or time slips with A/B comparison would be solid data. And, Shell would probably add your testimonial to their site making you famous and sought after by hordes of large breasted, scantily clad groupies eager to bear your children!
Lucky for TC, he lives in New Zealand and has access to Shell Optimax, so he can try it for himself, and decide whether his "seat of the pants" opinion carries more weight than your "wannabe-technical" mumbo-jumbo, ha ha! Cheers, Terry. 
TC can buy whatever he wants. I'm just trying to help him spend his money to best effect. If he feels better with Optimax in his tank and a lighter wallet, then by all means continue. I'm fairly certain Shell will gleefully accept his and your money for your continued happiness. Many evangelists owe their livelihoods to people of faith and hope. It's, sort of, a free country.
If you want well written mumbo jumbo, peruse the entire Shell web site. (Sound and fury signifying nothing, except "BUY ME".) They have learned lessons well from many snake oil salesmen who did and did not receive tar and feather apparell, as to just what can be stated or claimed about their product. Other oil companies are no different.
Or, please point out where I missed the statement or specification about the increased energy content in the fuel they sell over their competitors or any other product even THEY sell with a lower RON. But, I warn you, if you think my posts are painfully long, you're going to be in abject agony reading that web site! Better have some vegemite and a keg of beer nearby for a sustaining boost.
Okay, I admit it. I added a lot more to this post than I needed to, just so Terry's eyeballs dry out and permanently glaze.
Jeez, sometimes I'm just soooo mean...
