Shell nitro plus 99 octane

Higher octane is slower burning so as someone here mentioned earlier, you don't want to run any higher octane than you need. Specifically, higher compression (via heads and/or pistons) and advanced ignition curves will benefit from higher octane and yield more hp and mpg. The higher octane doesn't give you the higher hp and mpg; it's these mods permitted by the higher octane. Better tune via optimized A/F doesn't need more octane; as such, exhaust and intake mods don't require higher octane.

The energy density of ethanol is about 25% less than gasoline. The "biggest" boost to your power will come from finding a gas station that pumps ethanol-free premium. You will get more power simply because the energy density of your overall fuel mix will be about 0.025% more when running fuel that does not contain the 10% ethanol (25% increase in energy density X 10% volume of the gas replacing ethanol = +0.025%).
Some claim to notice a difference in their OEM motor; I do not. Regardless, I try to buy ethanol-free fuel for my bike whenever I can.
I do not think it is a big deal for any USA vehicle that is a 2007 or newer; however, my understanding is that for those vehicles older than that, the ethanol will erode the integrity of the rubber and seals in the fuel delivery systems because pre-2007, vehicles were not engineered to take the 10% ethanol mix, which corrodes the rubber/plastic.
Of course, the exception is all those out there with plastic tanks. If the inner coating on your plastic fuel tank is breached, your tank may expand and distort.

Styler said:

Of course, the exception is all those out there with plastic tanks. If the inner coating on your plastic fuel tank is breached, you tank may expand and distort.

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Ethanol is the primary reason why I refuse to entertain the idea of owning a M/C unless it has a metal gas tank.
Too many horror stories....

Every horror story I have heard regarding ethanol is when people let the bike sit. As long as it is constantly ridden it isn't an issue.

Phase seperation is what its called. Anyone who lived in a seasonal climate when ethenol went mainstream knows what kind of havoc it can wreak; snowmobiles, chainsaws, weedwackers, ice augers... 2 Strokes hate the stuff because the water seperates over time then you drink a slug of it and your all done.. 4 strokes are a little more tolerant to seizing but even if that stuff sits in your carb for the off season 2 stroke/4 stroke whatever; your all done..
http://pure-gas.org

We have the option in Australia to use the 10% ethanol mix, it is cheaper but does get less mpg, I was using it in my 3 series for my 80 km commute to work and after about 3 - 4 months had to replace all the throttle bodies, engine warning lights on and the car would go into limp mode, I don't use the ethanol mix anymore.

Claymore said:

You would need to be able to adjust your timing if you want to utilize higher octanes. By just tuning the air fuel ratios you would not get an increase in power with a higher octane.

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this, at a minimum, to see any performance gains. as stated above, higher octane fuels burn a bit more slowly and in a more controlled manner, which lets you advance timing and bump up the compression ratio. The former is simply a matter of mapping; the latter requires significant engine work, although you can achieve higher compression on some motors by using a thinner head gasket.

ignition timing on a non-forced induction motor isn't so straightforward though - MBT isn't always at the most advanced timing before detonation.

I've heard that high octane fuels contain slightly less energy as well (disregarding any ethanol blends), but that's just hearsay.

I will say this though - from riding with people who honestly believed race fuel made them faster....it didn't obviously, but the exhaust does smell pretty nice. Kind of has a sweetness to it.

AHHH, I miss that smell of Race Fuel in the morning!!

Smells like..............................