Before I had a piston finally let go at a total of 114k miles, over 85k modded miles:
~38k miles at ~22 psi on my 20G making 285tq/325whp 93 octane and
~7k miles at ~26 psi on my 20G making 335tq/360whp 100 octane
I don't think the piston would have failed at that time if I didn't use 100 octane from a pump as I suspect bad gas.