I think there are filters that are sold as upper tier - Wix XP, Purolator Boss, etc. That if you weren't a member of this forum you wouldn't expect them to have poor filtration efficiency.Well, it was done by an acquaintance of mine, and those were the products he chose. I'd also have to say you and I would likely agree; nobody wants a 50%@20um filter (Wix XP?). MOST of the decent filters are going to be 85% or better in today's terms.