A performance of an oil huh ? Well, if you can read and understand TD sheets, that would be a huge start. I have many documented proofs as well from fellow excavators, truckers, loggers, and everyday regular users of Schaeffer products. Just as a recent example, 1 towing company by me who uses both our 15/40 and 10/30 diesel oils for their Powerstrokes and Cummins has reported back to me that the drivers are seeing an app.10* lowered temperature change, a quieter engine, and slightly better mileage. Am I going to get a written statement notarized just for you to help prove a point ? That's a big NO. Then we can step up to oil analysis for justification. Being a user of many Schaeffer oils for the last 18 years in my excavators, dozers, backhoes, dump trucks, and personal trucks, I have never received a negative report once. So again, I know the high quality of Schaeffer products, my excavating friends who I sell to know it, my car club friends know it, whether you believe it or not I really don't give a rat's azzzzz but I do know that our founder Bob, the original Schaeffer rep would back me up 100% as will many other Schaeffer users here.