I actually really like these filters in ST and FramDrive guise. K&N uses them too and M1 used them prior to the PuroBoss switch. No issue here.
I do to and I am not at all worried about the e-core in the RP filter, the wire mesh should absorb most of the pressure from the oil flow so the e-core center should never be too stressed while in all likelihood providing much better flow characteristics. The rest of the can is built to racing specs so in reality I think this is a Royal Purple product that is totally worth the price.
...does RP mention any efficiency at all?
On RP's website they say 99% @ 25 microns and 80% @ 10 microns. When Ascent Filtration tested them the efficiency was just a split hair below the Fram Ultra so they might actually be better than what they report or perhaps the media is now the same as what the Amsoil filter uses that is rated at 99% @ 20 microns. Either way it is splitting hairs difference between it and the Fram Ultra.
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