91 vs. 93 octane [by (r + m)/2 method]

I've noticed that many SVXers on the boards are using 93 rated octane (where available). Here in Cali, the highest rating available is 91. This is also the minimum specified rating required by the SVX.

I've heard different opinions from different people, but does it really matter, in terms of better performance, if you use a higher-than-minimum rated octane?

Some people say the increases in performance are negligible. Some people say it definitely makes a difference. I, personally, can see both sides of this argument. I could understand why using 93 instead of 91 wouldn't make a difference, since your ECU creates the timing advance of the spark in presumption that you are utilizing 91. Then again, I could see the 93 taking advantage of this advance since it combusts more efficiently than 91. I'm no performance pro, but by simple logic, these are two possible sides that I see.

Would the knock sensors notice the difference between 91 and 93? I don't know exactly how the knock sensors function, but I understood that they only look for detonation.

I'm just sort of thinking aloud, but it is something to consider with the price of gas rising at such a ridiculous rate.