Quote:
Originally posted by John Doe:
If you don't have a supercharger you are wasting your money on anything above regular. The 91 octane requirement is for the supercharger models only (reread the manual), all others only require and do fine on 87 (85 at altitude) octane.
The manual does say " for optimum performance use 91 octane"... I use 87 in average town driving, but my X likes 89 at high speed and gets 18-19 mpg at 70-75 mph. I wouldn't call higher octane a waste for long trips at high speed.