A couple years ago I was looking at some Purolator's on the shelf and noticed the louvers in the center tube weren't even opened, not even a little gap using my Streamlight pen light. There were multiple like that on the shelf and even found some at a different store the next I was doing an oil change just to see if it changed. Ever since then, Purolator isn't even a consideration for me.
Plus their filter selection is odd. Their highest tier 20k filter (gold) has unknown efficiency specs, the next tier is their BOSS filter rated at 99% at 46 microns as well as being rated for 20k??, then their mid-tier ONE filter is 99% at 20 microns. Wouldn't the Purolator ONE be their best filter then??? Make that make sense....