Toluene [or toluol]is used in octane boost. It won't make any differance in HP unless your engine calls for a higher octane fuel, ie:advanced timing,high compression. Otherwise using an octane booster in a stock engine will yield no gains.
To make octane boost use:
1) 100oz toluene [octane booster]
2) 25oz diesel fuel [cleaner]
3) 3oz transmision fluid (lubricant]
I don't think it would be wise to use this in newer cars as it may ruin the oxygen sensors.