higher than required anyhow. The way it was explained to me, higher octane has more additives to prevent detonation, and this will not burn as well, getting you worse fuel mileage than you should see. I was told a friend's mom got 2 MPG back from switching from 92 (which she didn't really need) to 87 (which was recommended)... any thoughts?
Tim Collins '90 535i 5-speed sharked, drinking the good stuff... at over $2/gal...