Compression is a limiting factor in the goal for increased horsepower. With a stock low compression piston yes you can run low 87 octane gas but your engines overall efficiency will not get the most power out of that fuel you put into it. Basically stated a higher compression ratio takes the air/fuel mixture that is draw into the engine and squeezes it harder than a lower compression ratio would. The result is a more powerful bang when the spark plug ignites the air/fuel mixture, resulting in a more efficient more powerful engine. Yes you will probably need to run higher octane fuel, either 92 octane premium or higher octane rated fuels or a mixture of the two. A higher compression piston can be worth as much as 3-6HP that’s a performance increase you will definitely feel.