I backed out of this thread awhile ago but it sure has some legs. It is worth noting that ASTM D975 sets lubricity wear scar 520 on HFRR test. Fuel suppliers have to meet this before they can market the product. Bosch, however, recommends a wear scar max 460. Their research shows that running with ULSD over this will lead to mechanical damage. Additionally, they recommend "first fill" on new engine has a max 400 wear scar. Biodiesel is the best lubricity improver out there, which is why I run 2% blend. Cost premium is minimal except it is hard to find retailers who can supply a product that meets industry standard. I would not use home brews on a CR engine. It is my understanding that Stanadyne PF (8 oz per 30 gallons) meets the Bosch lubricity standard. Running B2 I don't need that but the additive is approved for blends up to B20. I run Stanadyne PF for the other improvements it offers:Cetane boost, water removal, anti gel etc. The fact that most engine shops market this product, and sell a lot of it at $7/pint, is something to consider. I am skeptical of the mileage improvement claims and I have not been able to verify them. That is not why I use the product. I use it because I believe the additive improves fuel quality, which has long term benefits in engine performance (ignition quality) that perhaps can not be measured but should extend engine life. For $3. 50 a fill up it makes me feel better.