Living in NE Ohio, I get to enjoy the highest unemployment and poorest large city (Cleveland) in the nation. I was unemployed for over a year, now have two part-time jobs that pay OK, but I have a lot of catch-up to do. So, don't get on my case about this! I'm trying to save some money!
In the winter last year, I ran 89 octane in my SI instead of the recommended 91 octane. With the slippery Cleveland roads, you don't dip too much into the accelerator anyway. The manual says you can run ONE tank of 87 octane, which I have never done, but 89 octane is cheaper than 93. This past summer, I filled with 93, then refilled at half-tank with 89, figuring they averaged 91...
Anyway, any trouble running 89 for the cold weather, so long as I don't lug the engine on upgrades? Just downshift to keep the revs up, I've heard it requires less octane. Does this car have a knock sensor? I've never heard detonation, but then again, I never tempt trouble if I don't have to.

 

what stuff do u sell in the US !!!
our unleaded is minimum 92 and premium is 98 !!!

 

Octane can be RON (research method) or the other "motor" method. Our octanes are an average of the two, go figure.
Very high octane without lead is very expensive, and the US seems to think cheap gas is a birthright. I'd be willing to pay more for gas if it would teach the idiots in their over-sized SUV's a lesson! There are way to many land yachts that people get just for the heck of it.
Anyhow, Honda recommends 91 octane (premium), although I see 92 and 93 octane premium, and Sunoco has 94 octane as well, if 92 isn't enough for you and you like spending money on gas. I can see it, in a highly modded engine with high compression pistons, or a turbo.
Dean