[cobrashoch]

I'm going to put a spin on this from another direction. There is a old hot rod addage that says something to the effect, that if you get any improvement what-so-ever by switching fuels you probably have pre-ignition of some sort. Guys typicaly think that pre-ignition is pinging and/or burning a hole in pistons. It's that, but more to. If you get better milage or just get a bit more power by tuning that's pre-ignition. Pre-ignition is insidious, that is, you may have it but don't know it. That and the fact that most engines will tolerate some amounts of it makes it a hidden problem. I feel that that octane boosters are band-aids to the real problem. Since it is possible to get huge horsepower numbers on pump gas I suggest that a better way to do things is to tune your engine for the fuel that you want to use. It IS time consuming though. I have found that about 80% of the time pre-ignition is a problem with carburetor'd engines to. I don't mean this to be a war of carbs vs fi as I am a carb guy. But those are the facts I have seen. In any rate, using either method, proper tuning in most cases will get you more power to!
cobrashock