Don't know if it was serendipidous or not, but about after 1 month of using Redline DFC, I noticed a slight loss in power on my 1977 300D. It might have been a bad tank of diesel as well. I changed both fuel filters and was amazed at the improvement in performance.

A good indicator is to get some light on the clear fuel filter, I can best see mine from under the car, and see if there is any sediment in it. I noticed mine while I was changing motor mounts. After this experience, I change my clear filter about every 1-2 months. It helps me keep track of what is going on.

Good luck,

PS, coming to the diesel meet?