Hi Armando,
Great to have someone new commenting.
I read through the article a couple of times and I feel there are 3 salient points missing. First is they do not give the surface area of each filter, secondly they do not say how much surface area was presented to flow and were all the filters the same shape?
The first point is obvious surface area is all important in a calculation/test like this. The second point is equally important, if one filter was flat to flow it's going to have different flow characteristics to an oval/conical shape filter. The area at the back of an oval filter will be in an eddy - turbulent area. Again the shape of the filter greatly affects flow through it. In my view this kind of makes the tests meaningless.
One point is true though; when it comes to a filter with an oil film it has the potential to clog faster than a plain paper filter. The dirt will coagulate with the oil and block the filter, hence the need to clean oil film filters more regularly than paper.
As for claims your engine and system are set up for max performance, we all know this is not true. They're set up to pass very strict emissions tests. Take for example, I was once looking to take my 6 month old BMW bike to the US with me as I was planning to be there a number of years. After talking with BMW at both ends, I had to jack the idea due to the incredible emissions standards required. The bike in the US was strangled compared to the EU model! The harder the emission standards the more power you loose. Removing all the emissions crap will always improve power so long as it's suitably re-tuned.
I think most will agree best performance will be seen with the bike set up correctly to run with an open Velocity Stack however there's a lot of tuning for our bike to run in that format i.e. Stage 3 level.
When I chose to do the K&N swap I took into account the generally held view that the MT-01 runs rich and I chose a filter with a comparable flow area to that in the standard box, although flow around it is entirely different. To be honest I'm not expecting a big gain in power I just didn't have the heart to put that big heap of plastic back in the bike, weight alone must give me a second on the 0-60

Cheers
Max