QUOTE (DJKOR @ Nov 1 2009, 04:46 PM)

From my own experience, I have found there to be barely any difference between regular 91 octane unleaded, 95 or 98 octane premium unleaded, or E10 ethanol... when doing sedate highway driving. For that kind of work, when the engine just keeps on running at around 2000 RPM and doesn't accelerate hard to keep the revs as low as possible, either fuel works just as well. E10 though would be the most cost efficient for this scenario.
But as I said, this is from my own experience. Your mileage may vary (no pun intended).
after 1 day of running 98 sugar fuel the economy went up to 11.8 lt after that refilled with 91 ulp 10.6, i keep trying but mine is happy on the fuel thats rated for it even with the mods.