I lived in europe for a few years and I also noticed that the octane ratings at the pumps were higher then they are here in canada. However this is not because the gasoline is different, here is a quote from good 'ol wikipedia:
" In most countries, including all of those of Europe, and Australia, the "headline" octane rating shown on the pump is the RON - but in the United States, Canada, and some other countries, the headline number is the average of the RON and the MON, called the Anti-Knock Index (AKI). It may also sometimes be called the Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2 "
If you look at the table
HERE you will see that "premium" gasoline in canada/the US labled "around" 93 octane at the pump actually IS 97-98 octane gas (that's what it would be labled as in europe & elswhere).
I agree with
give me vtec regarding imports - locally I can also only get "91 premium", and although my car (92 eagle talon AWD turbo) runs fine with it I do see a small performance increase when I have a chance to fill up with "93 premium" at a out of town gas station that has it. This has to do with with the cars knock sensor - timing will automatically advance as far as it can before knock is heard, the higher the octane the further it will advance.
To the OP: you should be fine running your engine on "regular" gasoline. You MAY see a little performance increase running a higher grade, then again you may not. "Regular" gas may actually perform better in a small engine as it is easier to ignite. Depends largely on the compression ratio, timing and the load you put on the engine (premium may perform better under high loads). Many honda (and other) cars run high compression (10 to 1) even on "regular" gas, then again as I said cars have knock sensors which will adjust timing automatically. Just give it a shot, won't hurt anything. I tried running "premium" in my HT, made no difference at all, not really a surprise with the low compression ratio (~6 to 1) that these things have.