A lot of factors affect octane need, often forgotten are altitude and temperature.
I have tune that calls for premium gas.
I run regular 87. Am I tempting the gods?
I don't think so. I live at 4700' it is 12 degrees now. Still, I run rug in the summer. I hooked up my scanner, floored it a few times, drove around drivin g it easy, driving it hard and saw no knock retard, engine sounded fine to me.
'96 Impala bought new, with every bolt on imagineable
'06 GTO, headers, dyno tune, almost every stock suspension piece replaced with stuff that isn't crap!
'03 Jetta Wagon TDI, large injectors, euro tune, vr6 clutch, it is fast and gets over 45mpg
'91 Katana 1100.
'11 Kawasaki Concours 14