Here's the thing, and I'll summarize:
Timing. (That, or boost/compression, but we won't get into that.)
Most often, the reason the factory recommends premium gas is because the timing is set "aggressively" to make more power. (Again, that or the car has a turbo/supercharger.)
You're timing is controlled by the ECU (computer).
If knock-sensors read a knock, the ECU retards the timing.
Retarded timing yields less power.
Less power means you have to push the pedal down further to compensate.
The result is more burned gas.
The result of more burned gas is the same amount of money is spent, if not more.
Bottom line: you'll fuxup your car and spend as much, if not more money, by putting in the cheap sh!t, so don't.
Oh, by the way, I've heard countless mechanics and "factory trained technicians" tell fools "yeah, run the cheap stuff, it doesn't matter". Right. That's good business. Recommend that a person fux up their car so they have to bring it in to you to get it fixed.
The factory would love nothing more than to have a consumer purchase a car every 3-5 years, so they train their technicians accordingly.
I can rant and rave about the benefits of premium gas over the cheap sh!t for hours, but it will be useless. Just as males are hustled and fooled into turning their backs on their masculinity, the American auto consumer is brainwashed as well. People will argue up and down that the grade of gas doesn't matter.
No?
Then why are there 3 options to begin with? Why not just one? What's the difference between the 113 octane you get at the track or jet fuel and 87? Nothing?
Nevermind, then.