The biggest benefit racing gasoline gives an engine is higher octane, which gives your engine more power. Also, the boiling point is higher, which helps prevent vapor lock.
High-octane fuels have less uncontrolled combustion than lower octane gas. Modern engines typically account for the octane level of the fuel and alters the timing in the engine. Racing fuel is harder for the engine to burn, so a decrease in horse power may occur. If the engine is not designed to burn racing fuel, it may gum up the pistons and create carbonation problems. Also, there may be no benefit if the engine does not have extras such as turbo, high compression, and nitrous.