Hey Wes... no reason to run premium on a stock GT. Get a CAI/ Tuner combo and then you can have different tunes to take advanted of say an 87, 89, 91 or 93 octane setup... depending what octanes you can get in your area.
Using a higher octane gas doesn't make your car run better. What it does do is allow you to alter your tune, i.e. spark advance to gain performance. If you did this without using higher octane your engine would detonate and you wpuld be sad.
The point is that using better gas isn't going to help you if you don't alter the tune. Save you money and buy 87 unless you hear pinging then move up a grade until you don't.
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