The M1 and KN oil filters share pretty much the same "skeletal" structure. The KN adds the head nut, of course, and seems to have a somewhat thicker shell. Both are made by Champion Labs. When you cut them open in unused condition, you can see how the innards, apart from the element, are virtually identical. Where they part company is in the filter media. Mobil advertises and emphasizes fine filtration. KN promotes the filter as flowing more easily (but probably at the expense of filtration to some extent). When the filtration media is clean, you can see a color difference between the two. That's meaningless in and of itself, of course, but it does indicate that each seller is calling for a different media. I've used both, and reviewed a great many UOAs in which these filters were used. You should be just fine with either one.