Naio,
I use whatever gas in my little EX650 ... and sometimes keep Stabil in it's gas storage can and sometimes not. It has never seemed to care much about the gas I use in it.
It was given to me back in the late 1980's in like-new condition and still looks and runs like new. I use the most expensive synthetic oil in it that I can find - Mobil 1 Extended Performance. I also use an E3 spark plug for a slightly less labored, smoother sound and longer run time per tank of fuel.
You can also use a shot of SeaFoam in it's tank once in awhile. :)