I have one local station with NO ETHANOL 91; if I can't there. by 2nd choice is Shell 93 Octane (has ethanol in my area). Noticed a huge difference in performance with the non-ethanol on my 2010 535I, not quite as much on on the 2011 535I.
2011 535I X-Drive - Space Grey / Black Dakota / M-Sport / Sport Automatic with Paddles / Premium I / Premium II/ Cold Weather
Gone 9/20/11 - 2010 535I - Alpine White / Black Dakota - Sport, Premium & Cold Weather Packages, Sport Transmission, Anthracite Roof Liner, Navigation, Satellite, HD & I-Pod
Gone - 2006 530XI - Monaco Blue / Creme Beige Dakota - Premium & Cold Weather Packages, Comfort Access & Satellite