There's no reason a disposable air filter can't be manufactured with cotton gauze as the media. "Serviceable" is just a design and marketing objective to get $50 for a filter. An inexpensive gauze filter could be applied to production vehicles just as well, but cotton does not meet mfg specs for media, paper does! Surely a pure race vehicle could afford a new filter after every event. They are not worried about excess wear or deposits anyway. So in my mind K&N is a product looking for a purpose.
Go back to the reason the mfg uses paper, it filters better. What is the primary of a filter anyway.....filtration, not flow. The mfg designs the intake around the flow rates of paper anyway, so what is there to be gained? Sure the perception of more flow sounds good, but really, once flow is adequate....more isn't better. The real difference is the .01hp the engine consumes sucking the air thru paper itself.
Again, your UOA looks good and I intend to reference it when we got our UOAs going.....but it doesn't tell you anything about the dirt flowing onto the dry valves. Not that VW engines are difficult to clean the valves, I just use some CRC GDI every Spring for this. In my case am more concerned about excess wear in the upper cyl and rings. My DD is a Neuspeed 2.0T EA888 Gen2 Valveluft w/40 k that doesn't burn oil. in NO WAY would I risk dirt coming into the intake and wear my rings out. A tiny little part that would be almost undetectable in UOA until it was too late, nope. I doubt you'd disagree.