I have been reading this thread with interest. Years ago (2/87) CU tested oils & oil filters. In that test, Fram came out best. (The only ones check rated.) When taken apart and examined, they look like junk, but they work. I also like the black crinkled finish they put on, it makes it very easy to put on and take off by hand as it doesn't slip. I have used Frams for a long time, put over 200,000 miles on a 4 cyl Taurus, usually drive my cars until no value left, and have never had any engine problems. I don't know if the filters are still made the same, but in this test the Fram removed the most particles & did an outstanding job for all the filters they tested. They tested Lee, AC, KMart, Motorcraft, Purolator, and Sears. Many of the filters showed variations among various models. A quote - "Interestingly, certain filters made by automakers for their own cars proved to be far from the best choices as replacements." I did not see where they addressed backflow issues. John