all it does is remap the ignition so you can run normal unleaded without it pinking. in the past the way to stop this was retard (i think) the ignition but that robs you of power. it doesnt do much in the way of "performance" and i personally dont think its worth it when fuels like optimax are available. you wanna look at the ron number, the higher the better and leaded is higher than normal unleaded.
