On cold starts, 99% of the oil going through a spin-on filter bypasses the media. This results typically in a 6-8 psi pressure drop across the bypass valve, depending on the engine designer's ideas about bypass valve settings. This happens on all filters, regardless of the filter media, since the oil viscosity is several orders of magnitude higher than at design (working) temperature. It may take several minutes for the oil to heat enough for the bypass valve to start closing, and unfiltered (hopefully, clean) oil is circulating during that time. When the oil is hot, the size of the filter outlet (the inside diameter of the threaded nipple the fliter screws onto) typically sets the limit of flow, not the filter media. A decade ago, we tested a dozen or so available filters using SAE 30 oil at 185 degrees, and pressure drops were within a pound or two of an empty filter can. This was on a small block 350 at 5000 rpm. I believe most filter engineers try to design based on the outlet size limiting filter pressure drop. (Note that one filter can't "flow more" than another, but it may in some cases have a lower pressure drop under equivalent operating conditions in an engine. The increased pressure to the oil galleries slightly increases flow, but only in proportion to the square root of the pressure increase, usually negligible.) Most hype about "high-flow filters is, well, hype. In my experience, lower viscosity oil is the only thing you can do to help flow during low temperature operation. A larger filter volume (longer can) won't help much with flow, but it will go off bypass more quickly. The engine oiling system is what it is. At operating temperature, filters will "flow" about equally, as well, regardless of cost or media type. The occasional filter which has a large pressure drop across the media should be scrupulously avoided. (Fram, perhaps?) Filtration ability is important and I choose on that basis, along with details on construction provided by members of this group, looking for strong housing and element design, and good bypass and adb valving. Most are fine, the ones favored by this group are likely the best.