I'm not one of those people who stresses over fuel, but one thing that it is very noticeable for me is that my US X5 35d is noticeable louder at idle than my dad's EU 325d... It seems the knocking is more subdued... I blame the different fuel available in Italy and Switzerland over the US. I'm not interested in steering up yet another debate and what's better or worse and why and the how and all that...
But in any case, if anyone out there has a 35d and lives in NorCal, I'd very intrigued to know if this diesel HPR form Propel is any different:
Propel Diesel HPR
I'm not about to drive up to Fresno to try it so hopefully they bring it down to us at some point. We have a few Propel stations, but none close by me has diesel, just E85. I have used their B20 many many time when I'm in Chula Vista or Kearny Mesa and never noticed any noticeable difference