Edit: I found a really good link....
http://www.wanderings.net/notebook/M...sWorthTheMoney
"Does High Octane Gas Give More Power?
No. Unless your car is explicitly designed for high octane gas (see your car's manual), using a high octane gas will NOT improve the power output of your engine. Again, the octane rating relates to how much energy it takes to ignite the gas, but NOT directly to how much energy the gas puts out. "