Like Julio said, it depends on what kind of boost you want to run. There is no doubt you can run more boost (and a little more timing) on 93 pump gas plus alky versus 100 octane.
If you are only running 17-19 psi boost with no problems on 100 octane, the only benefit you would get from alky would be in the middle of the summer to help negate any heat soak effects from a stock location intercooler. No worry about having to cool down between runs with alky.