[SuperTom]

Originally Posted by pfaffendorn

I agree with most of the guys that the air intake and exhaust header should make a small but noticeable difference. With no mechanical mods I just started a new diet of 93 octane non-ethanol and noticed a small but satisfying increase in all performance parameters. Of course, you have to have a reliable source for such stuff. If you live near a large lake frequented by power boaters, you should get lucky and find a filing station that sells good quality juice. Your engine controls will make enough of a change in the tune, and your boxer will love you for it.

Yeah you should have been using 93 from the beginning. Even in stock form they are designed for it.