Which fuel do YOU use

[thepartsmancometh]

my take (largely uneducated, but somewhat thought out):

higher octane gas only helps in a "non-premium required" car if the ECU is sophisticated enough to advance/retard the timing to compensate for knock. Most, if not all, modern cars can pull the timing (retard) when knock is detected. Many cars though will not advance the timing past a certain point; running a less knock prone fuel does not necessarily make more power because the engine cannot fully utilize the increase in detonation protection.