The way I see our turbo cars react to different gas, I am going to run the best shit out of the pump that I can find. Shit if the 111 octane gas from the Mobile by my house wasn't 3.50 gal I would run that gas all the time.
Our cars are so octane picky I don't know why someone would own one and try to cheap out and put some garbage gas in it. I mean shit if you have a 10 gallon tank and 87 octane is 1.70 and 92-93 octane is 1.90 you are paying $2.00 more for a tank of gas. It isn't that much of a difference.
Eric is right though, you cars ECU will protect it to some extent
but constant knocking/detonation will kill your car eventually even if it pulls timing to protect it. The cars asks for premium for a reason, its not a pich to make you think that if you do it your car will be faster, its just for safety of the motor. Our cars were initially setup pretty aggressive from the factory to begin with. That is the reason that they require premium fuel. Now if they were setup to run 5lbs of boost from the factory and not so aggressive timing maps and lower compression it would be a different story.
And I don't know if its been proven but I would be willing to bet that your fuel economy would be a lot better with a more efficient gas/burn.
But hey if you saved $2.00 a gallon and you filled your car up once a week, shit in 20 weeks or six months you could buy a Joe P boost controller with the money you saved, if your car lasted that long....WTF
CRAIG