Most filters work/filter better after a few miles & deposits clog up the larger pores some. Thats when filter surface area comes into play. The more filter area available, the lower the pressure drop/restriction flow across the filter media during its change intervial.
Our factory cold air air intake system isn't restricted for the factory engine at the RPM
range most operate in, so there is plenty of air flow margin as the factory filter loads over its scheduled change intervial. No need to fix what aint broke, the old timers use to tell us kids!!!! lol
But there is a difference in how well a filter removes & holds particles over time & the Mfgr specs are still the ones to meet or exceed & only so much filter media can be stuffed into the factory air box. So a filter that removes smaller particles is gonna need a larger airbox, to fit in more media surface area, so pressure drop doesn't get out of hand as the filter loads. We've already paid the factory to do the math for us when we bought the vehicle, so all we have to do is follow the instructions we've paid for!!!!! lol
A few years ago on the Cummins site, they were saying that warranty for scuffed cyls would be denied if oiled foam or cotton gauze air filter was used & they put up photos of scuffed up engine cyls as an example.
I'll just stick to the factory specified paper filters, changed as called for in the Scheduled Maintenance Guide, as those filters have to meet or exceed Fords specs.
Who knows what specification aftermarket filters meet, nor when the vendor will decide to change them to help his profit margin!!!!!
Same for oil, fuel, tranny, power steering & cabin filters that Ford specifies. Ever wonder what spec aftermarket filters are made to????