What do you consider "high silica levels?" Is this an accepted SAE method of determining air filter efficiency? I'm betting that it is not.
Every test that I have ever read indicates that the K & N filters are less efficient in removing harmful, abrasive particles than a high quality paper element.
I guess it is up to each individual to determine whether the lower filtration efficiency and the resulting increased wear risk of using K & N filters is worth a little more air flow for street use.
I defer to Blackstone labs and the report they submitted to me. My levels were all within the universal averages for my 5.7L engine. If the air filter is not doing its job it will show up in the OA. It will also show up in accelerated wear levels of metals in the engine. They were also well within the acceptable limits for my engine. In fact I was also running the Mopar M-090 oil filter. The same oil filter that every keyboard commando on the Mopar forums was saying was "junk". 15,000mi on a "junk" oil filter and "junk" air filter but at 120,000 on the engine and 15,000 on the oil it was clean and could go another 2,000-3,000mi under the suggestion of BL before another OA to check for oil life.
So, was it a crappy air filter but a really good oil filter? But the Mopar filters are Junk according to the internet. So the air filter must be really good, right? No, the internet says its junk. The only way to know what is WORKING for YOUR engine is to do a OA of your engine oil. Thats great that an AC Delco Duramax air filter works well. That does not mean dick for the Honda air filter in my Honda.
For me, it's not about airflow or performance. It's about disposing an air filter every 20,000kmi and filling up the landfill with air filters. Also, the $$$$ that goes with.
The SAE also says that it's OK for your car to burn 1qt of oil every 1000mi. Are you OK with that? At that rate I would be burning 2 qts a month and have to be OK with that because the SAE says so. Im not OK with that. Luckily over 10,000mi my Accord does not require any oil.
I agree with your last paragrap, kinda. For me, real data about MY engine at MY oil change intervals analyzed by a respected lab means everything. A fancy powerpoint chart of a Duramax oil filter means nothing on a Honda. Maybe the K&N does let a little more dirt in. Is it detrimental to your engine? Not on a 2005 5.7L HEMI.