I've used Sunoco 94 half the time and Citgo (premium) half the time and haven't noticed any issues with my 3.0 engine. We don't have any of those top tier stations here (unless Sunoco-Canada is the same).

Anyway, I'm surprised the big ones like Mobil / Exxon aren't on the list. I guess they're overpriced anyway. We were always told gas is gas... but I guess not if you have a demanding car manufacturer.

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'08 X5 3.0si - Alpine White / Saddle Brown interior
Specs: Sport Pkg, Premium Pkg, Tech Pkg, Comfort Access, Aero Kit, Style 433 staggered 20s on Conti DWS
Mods: Carbon 35 tint, LED angel eyes, GP Thunder 7500k fogs, H&R 20mm/25mm spacers, clear reflectors, gunsmoke-tinted taillights
Coded: Digital speedo, windows/sunroof/tailgate close via keyfob

X5 pics at Flickr