A lot of people (including myself) have said that its completely pointless to put 91 or 93 octane in your car thats tuned on 87. The reasoning is just because you have nothing at all to gain. Well if thats true then why do people 100 octane in sports cars that are tuned on 91? From reading different threads I know that there is a performance increase in the Elise (91 octane tuned) if you put 100 in it. So is it just that only sports cars can get any benefit from this?