very good post don.

the only variable i don't quite comprehend is the ecu - how 'adaptive' is it?
does it follow a standard timing map as written into the s/w and simple advance as much as the fuel in the tank will allow? if we run 5 tanks of 87 and then throw in a tank of 93 will we see timing advanced instantly, or is there a 'learning' period for the ecu to adapt?