I guess the basic point is you are taking a fuel designed to operate at one set of pressures and putting in an engine that operates at significantly lower pressures. My understanding is that for complete combustion to take place in an emissions controlled engine the temperature has to be within very confined ranges both to prevent knock and Nox production regardless of octane . The simplest test I can think of if you have access to an gas analyzer is have you engine tested for hc on regular octane and then on high octane. What you will see is a rise in hc on the high octane fuel. All that extra hc eventually will lead to more carbon and more hc dilution of your engines oil or in the vernacular turn your pride and joy into a sludge puppy
if the engine you test has a cat,all you need to do is measure the temp at the back of the cat. You will find the high octane fuel raises the temp of the cat about 150 t0 200 degrees,not a good thing at all. the normal temp differential of your typical working cat is 100 degrees,with the rear of the cat being the higher temp.