I agree with some of the above statements. The only times I saw tat race gas helped was when the cars were modified. My s2000 loved 112 octane
it would eat it up. I also had close to 10K worth of work done in the power department. You will know that you are gaining power when it takes the engine less time to hit redline! I ran 112 for about 2 months till I destroyed a racing test pipe from T1r... thats right I destroyed it!
S2000's are known for hot exhausts but with the racing gas I cracked and disintegrated all of the welds in the test pipe it literally fell apart. I have it as a trophy in my shop and had T1r send me a brand new one saying it just fell apart one day.
But any way like others are saying if your car is not tuned to use high octane you will loose throttle response and power. I had an emanage ultimate that allowed me to adjust everything for my fuel and performance parts and I saw a good 17hp increase by going to 112 octane. Be safe with your fuel the stuff can get dangerous for you and your engine. I have 10 gallons of experimental race gas thats close to 120 octane and if you get it on you it evaporates instantaneously... some pretty cool sh1t!