I use 91/93 high octane only because the quality of gas is so variable. "Mid-grade" is what is recommended for the LT and that's just fine if the timing is correct...
In the UK, I've had many people tell me that 'Brand A is better than Brand B' (substitute your favourite and disliked names for A & B
) but I don't know how they arrive at that conclusion.
My house in the UK is about 15 miles from a regional fuel depot. If you go there, you'll see Shell, Esso, BP, Q8, Jet and all the other tankers all filling up ... from the same filling point.
Unless the tankers themselves have the oil industry's equivalent of a philosopher's stone in the filling system, they all contain the same fuel (different filling points do give different octane ratings, though.)
What does seem to make a difference though, is when the tanks at the gas station were last refilled. If you fill your gas tank shortly after the station has had its tanks refilled, you stand a fair chance of getting a sample of the crud which had previously been sitting on the bottom of the station's tank.
I use mid-grade (95 RON) (91RMA?) and the bike seems quite happy at any speeds. I thought the Motronic unit was supposed to adjust the timing and it was calibrated assuming mid-grade fuel? (Or is its main purpose to throw out a cloud of black smoke if you open the throttle quickly?)