I just noticed recently that the place I usually fill up (which is the cheapest) is Murphy Oil and they seem to be running B20 ( or something like B5-B20) so I am good , I guess.

Interesting that used HDEO is somewhat beneficial in the referenced study. I am hesitant about that....

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)