High ocatane gas in an engine that doesn't require it is not going ot make any more Hp.
The Octane rating is an indicator of what that flash point (How hot before it ignites) of the gas is. The higher the number the higher the temp required to ignite that gas. It expands when combusted to the exact same volume that regular gas does. So weather you burn 1 milliliter of 87 or 93 octane gas it will expand to the same volume of gas. Where your cars performance and octane come together it the compression ratio of the pistons. The higher the compression, the more power an engine can make. A 10:1 engine is less powerful than a 12:1 engine. BUT the higher the compression the higher the fuel/air misture gets (remember your Chem classes you slept through) In order to prevent predetonation (engine knock) in a high complression engine you must run the higher ocatne fuel since it wont ignite until a higher temp. Almost every high compression engine will retard the timing of the spark IF the engine starts to knock. THis happens if you accidentally put in 87 instead of 92 octane gas. When it does this you will loose power. The opposite does not happen in a lower compression engine if you put in higher octane gas. No amount of electrical gadgetry will increase your compression ratio, that is a fixed number. So putting 93 octane in a engine not designed for it (high compression) will not get you any more power. You actually could loose power if your ignition system id designed to provide spark at a set tempurature and pressure and you change this parameter. You would need to set your spark plugs to adjust for the higher required temp. Adding a turbo, supercharger, NO2 are ways to increse the effective compression ratios (by forcing in more air/fuel) of your engine. This is why you must use higher octane fuel in those situations. SOOOOOOO, the long and short of this rambling is that an engine designed for high octane will loose power if given lower octane fuel. An engine designed for 87 octane will loose power if given even lower octane fuel, but neither will increase power if given higher octane fuel. Now as a side note you can advance teh timing a little and get a slight increse in power the determining factor still comes down to cylinder pressure which is controlled by the compression ratio.
Unless you do a FrankenMotor like HEK mentioned (there is a ton of room in the engine bay
), install a power adder (NO2, Turbo, Supercharger), or rebuild the engine with performance in mind (Higher compression, better valve timing, and some head work), we are stuck with what we have. Maybe a few ponies from I/H/E but not much.