Well, in my opinion and around here in Minnesota the "good stuff" happens to be 93 octane because that is the only thing available with no ethanol. I have snowmobiles, boats, lawn equipment and now this pioneer. Sometimes the gas sits in that tank for a long period of time before its used up or freshly re filled. Not to piss off the farmers here, but ethanol gas, as many on here know or should know is a small engines worst nightmare. I could go on and on about the pros and cons of ethanol, but that's for another conversation. It can ruin rubber parts like someone said, but it also attracts moisture, keep that in mind. I would probably run a lower octane fuel (87) on a fuel injected four stroke if I could find it without ethanol. If I used my stuff every day, I would have no problem with fuel with ethanol added, I run it in my truck, with no problems.