Fixit is once again exactly correct.
Octane booster, or racing gas, does not "improve performance" really. Octane increases will help to, or eliminate detonation.
Now that may allow you to increase timing (or maybe not) in order to increase HP. However, just tossing race gas in your tank, while it smells good, will not instantly increase HP. If the motor would take more timing, and said increase in timing would give you improved results, then yes. But normally, if you have 10:5 comp, you are only preventing detonation when the motor is already at its best timing.
So do not waste money putting two cans in, when one will work. Also, if your car runs good on 93 octane, do not blow good beer money on race gas.
Mr Mustang is also very correct, but I fell asleep reading his post
Eric
