Hey, where do you guys get the facts that higher octane will give you more horsepower? That is a myth spread by people that do not know anything about octane. Octane has to match your compression, period. The higher the compression, the higher you need your octane. Just putting in higher octane without increasing your compression will only turn your spark plugs brown and make them foul.
Think of it this way, you have 11:1 compression. You use 87 octane. The air/gas mixture will not be enough to stop the gasoline from exploding in the combustion chamber. There has to be something in the gasoline to stop this explosion and make the gas burn all the way from the top of the compression stroke to the bottom of the stroke. So if you put something in the gas to make it burn at a slower rate, you call that octane. Putting in 94 octane in the 11:1 engine might make it but it would be iffy and octane boost would be recommended.
For more horsepower, you have to add something like nitrogen to the gas, something that will make it the gas expand more quickly and still have the octane requirements.
Higher octane doesnot mean more HP.