dab86,
Phil is correct the best way to go about it is to get some good data on your car running the wonderful 91oct we have here in Las Vegas. This will give you the needed information on how your existing tune is performing with the fuel change. We would be more then happy to help you with this, and with our in house Dynojet 224xlc chassis dyno, HP Tuners, EFILive support we can accommodate any of your needs now our in the future.
Sam