I hope this has not already been discussed already, but has anyone done any testing on the performance differences when using 91 octane or 93 octane (or higher) on the '13 Shelbys with the stock tune? I know us CA owners have been told that 91 was the only option, but I know of one place (I use it to fill the jugs for my track bikes) that has 100, 98, 94, and 87 at the pump:rockon:. If ford recommends 93, I assume our cars will perform better with that level of octane resistance.
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