The computer will take care of the timing and adjust for your low octane fuel, power and mileage may take a small hit. You will have to test it to see if it will matter much and if it is worth it to run the better fuel. I bet it won't matter one bit on the highway, but towing may be a different story.
“She may not look like much, but she's got it where it counts, kid. I've made a lot of special modifications myself.”
— Han Solo