I believe Sams club may be like Costco in that even if they don't have your tire they can order it. But I agree that you should consider getting the tire that's made for your vehicle. IMHO the one your considering may be the wrong choice for your BMW. Vehicle MFGS recommend tires based on many factors, suspension being one of them. Remember the wrong choice may be unsafe at any price.

__________________
"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…….