Another octane thread. The octane rating on gasoline and gashol has nothing to do with how much power your engine will develop running them. High octane fuel (93+ or 91+ depending on your state) is used for IC engines with high cylinder compression, knocking or pinging problems, or to prevent early detonation.

Therefore, the Honda-Acura cars that require High octane are Integra GS-R/TR, S2000, Civic SI, Accord V6, NSX.

You will not notice any difference in power, because there will be none in your naturally aspirated, low compression engines. If you change your cylinder compression, or add a turbocharger, or experience engine knocking, use the higher octane fuel - your owners manual will tell you also. In that case, running 87 or 89 octane in cars that require high octane will exhibit a slight loss of power - this does not go the other way around.

BTW, you can get 'Octane Boosters' from any auto part shops that you add to your tank before fillup.