I spent the day with a friend who races IMSA GT3 Porsches and he gave me a little tip on a "illegal" race fuel formula that increased his dyno HP / Torque curves by 8% over the normal 100 octane Sunoco race gas he normally uses. The formula is as follows:

10 gallons of 91 pump gas
1 gallon Toluene (Octane booster that prevents pre-ignition)
1 gallon Propylene Oxide (Oxygenator that increases 02 in fuel by 37%)

Warning: Use gloves and safety precautions when handling the PO !

I'm going to give it a try at my next event.