Regular vs Premium. Been discussed over and over.
One tank full won't harm anything... Just drive.

http://www.xoutpost.com/bmw-sav-foru...69876-gas.html

__________________
"What you hear in a great jazz band is the sound of democracy. “The jazz band works best when participation is shaped by intelligent communication.”
Harmony happens whenever different parts get to form a whole by means of congruity, concord, symetry, consistency, conformity, correspondence, agreement, accord, unity, consonance…….