K & N air Filter...worth the price?

[Kaps]

For $35 on amazon the AEM dry filter not only flows better than OEM, protects really good too. When I inspected the inside of the stock air box (top side) post filter, I was expected tons of dust after 40k miles using the AEM. It was actually clean to my surprise.

I think it filters down to 1 micron. A human red blood cell for reference is 5 microns.

So AEM filter is same thickness as French President = 1 macron?

 

[Mriddle]

I recently put a drop in K&N filter in my 2018 Mazda 6 sport and haven't noticed any difference. But what I did notice while doing so was Mazda put what looks like a secondary fine mesh filter on the top of the airbox that can't be removed any ideas on why they did that and if it's restricting air flow?

 

[Nevada CX5]

Probably a California thing. My 18 CX5 has it too. thinking about cutting it out.