Devils Own WMI kit question

In my case, i just have 91 in my area and no ethanol either so i benefit from the octane boost of the mix. Injecting meth only when needed, remain cheaper for me because i daily drive it most of the time and i'm not often under boost....I sometimes boost below 3k by reflex to follow the traffic. That added knock resistance at the worst point is probably good for my engine bottom end too...