the only effective octane boost i have found is Torco accelerator, which will turn 91 octane pump gas into 96 octane with ONLY 2oz per gallon, which makes it way cheaper than toluene, where you need to add something like 20oz.
Compare with most store bought, they do -1 (yes negative!) to 3 at the same concentration, and usually cost more.
Most of them dont even say what they do, only they "treat up to 16 gallons" or "more power than other boosters!!!!!!!1"
You can also reduce knock by chemically changing the air intake temp (to the cylinder) by adding 1.5oz per gallon of acetone to the fuel, letting you run a map for +1 octane over your pump gas value.
Also upper cylinder lube will reduce heat output by friction, having the same effect, but smaller. Too much UCL will result in reduction in fuel output power, I use a custom mix which is 5oz for 13 gallons of fuel, lowers engine wear/temp and provides greater power, any more and the power drops.
You can use all 3 in combination with all working together, and get a nice 95 octane blend with 1.5oz of torco and acetone, and 1/3oz of UCL for every gallon of 91 octane gas.
That being said, torco has MMT in it, and is generally used in modified cars with the cats removed, and the spark plugs changed often. All non-ethanol gas over 94 octane WILL contain MMT, the rest have at least 10% ethanol. Shell 100 octane street/race gas is something like 20-25% ethanol.
A balanced mix for high octane with the least MMT and most power output would be E85 + toluene + torco + acetone + UCL, a lot of balanced chem would need to be involved to figure out the correct combo