Dan,
The reason my brother runs 114 in his jet ski, is because he has to. It has a lot of work done to the motor, and the compression ratio is way to high for normal "pump gas". Interestingly enough, he has a snow mobile too, and that he runs 92 in. No, you are right, higher octane doesn't mean it will go faster, or have any more power. It just won't cause an engine to ping, that was designed to run on fuel with a particular octane rating. When I had my motor built for my 77 Chevy, They made the compression ratio the highest it could possibly be, and still run on "pump gas". Most V 8 engines, in "stock" form, have a compression ratio of 8.5:1. You can get by on pump gas with 9.5:1. Once you go to 10:1, then pump gas just doesn't have enough octane.
Also, no one replying to this thread has mentioned computer controlled ignition, vs. non computer controlled ignition.
Guess me having an older truck, makes me a "sucker". Then again, I don't have high insurance, or monthly payments, and I have made back the initial purchase price, and all maint. cost at least 10 times over on this truck. I never have to worry about the 4wd light on the dash being on, and my 4wd not working because of a sensor either. Oh well....
~Chuck