that is all crap
more dependable cars run regular fuel because they are more dependable cars...not because of the fuel. They just happen to run on regular because typically they are NA Toyotas, which run on 87.
If a car is meant to run on 87, then no frickin duh premium makes little if any difference. Those two points should not even come up in the conversation because they are too obvious.
Now get a car that can run 87, but says premium recommended...like my old Saab. Running premium means usually a Euro vehicle where they dont have the twigs and moss 87 over there, 91 is their minimum. Also usually means forced induction, which should never be run at anything less than its recommended octane rating. My Saab got better power, mileage, everything running premium. On its regular tune. Tuned for 91? It gained 70 horsepower. Running 87 even on its regular tune you can tell it was pulling timing and the car felt real sluggish as the ECU basically put in REAL SAFE values as to not blow up the engine.
This thread can go in circles. In the end, if it says required premium - fracking put it in. If it says recommended premium...stop being a cheapskate and get it anyways...it is better for everything.
Honestly, 87 should just go away and 91 should be the minimum.