I got my letter 2 days ago. I was getting the long crank when I switched to Costco gas (saved about $.20/ gal over 76 gas). Dealer in Pacific BMW couldn't replicate it. I switched back to 76 and the long crank symptoms went away after several 76 gas fillups.
2002 E53 X5 4.4i
2008 E90 335i Sedan (Buyback)
2003 Infiniti G35 Coupe (Sold)
1999 Honda Prelude Turbo (Sold)