[Lynn]

I can find the ethanol free easy enough. There are several stations in Guthrie that offer it. I checked puregas.org, and other than REAL racing gas (which is overkill in my situation) and what I believe is a misprint (shows 87, 89 and 97.... I think the 97 is a misprint and it is really 91) no one has any 93.

I believe there is one Sinclair that has 92 in town. But... back when I was tuning my turbo BMW, I tried a tank and it pinged easier than the Shell 91 octane, so I am afraid someone is playing with numbers.

Anyway, thanks for the input. This is for Sherri's car, and it runs fine on the 91, but the manufacturer recommends 93 on this one. It has knock sensors, so the worst case scenario is that it is dialing back the timing a bit when under boost.
Thought we could try a tank and see if there is much difference. My guess is that it won't make much difference until the summer weather.