Re: Octane Booster... (AOx4)
That's not necessarily true, you can have pre-ignition and sub-par performance without noticeable detonation (knock) if running crappy gas. If you want the acid test, try 91 pump versus 94 or so on a dyno. I'd be quite surprised if you didn't see a slight improvement in overall power, given the utter crap they call gas in Cali.
Now, as to octane booster, the off the shelf stuff in the small bottles doesn't do a whole lot. At best, a can of 104+ or similar will raise your octane a few points. Say, 91.0 to 91.5 or so. As such, you're better off finding a source for higher octane fuel at the pump. It can't hurt to toss a bottle or two in, but it would end up being cheaper to simply get a drum of race gas, given what those octane booster bottles cost.
Alternatively, if you're brave, you can always mix your own with toluene or xylene.