How are you so confident I won't hear the difference? How do you know my listening skills are not on par with John Siau's ? Is it that you think he somehow got the testing protocols wrong or even worse, do you think he's cheating or lying?
My problem with claims is that they are just claims. If you read other's such as
THIS, you may well be convinced that's the best out there too. There are many examples, just check out Nelson Pass's, John Curl's, and many more. There are many of those gurus and amps that sell for tons of money.
http://www.milliondollarstereos.com/speakerlist.php?category=amps
You know by now I don't believe all amps sound the same, not without qualifiers, but one can go to the other extreme as well. There is no end to it if one believes in manufacturers claims. Think about this, rocket scientists don't succeed by just real world testing in the field even that is the final step. They learn/develop theories, do the design/calculations, experiments, validations, verification, and many more steps before test launching to prove that the product work as intended.
Back to audio, if amps all sound different base on mix and matching with other equipment as well as different people's individually unique hearing skills and preferences (such as the so called warm, cool, bright etc.) that are not easily measurable, how the heck did people like John Siau or John Curl design their products, whose ears/hearings skill/ability/preference would they base their design on? I would say their design parameters have to be based on just science, i.e. human hearing ability, noise, distortions, frequency response, power requirements, transient response, dynamic range etc, that's just logic. If the final products does well in all those categories, relative to normal human's hearing and discerning ability, then such products should, and will likely sound the same to normal people when used well within their specified limits, though the specs will not be exactly the same.