I am sure everyone has seen this:
http://www.duramax-diesel.com/spicer/index.htmI don't believe everything I read on the Internet either. So if you look at engines that are designed to run in hostile environments, i.e. earth moving equipment, mining equipment etc. Most if not all run some variant of the Donaldson Cyclo-pac set up. Also a quick glance at the million dollar trophy trucks that race in the desert and have engines that cost more than my buggy and the house it is parked in, also use this same set up. I am not trying to re-invent the wheel, or start a flame war. If you like jet doctors run them. The point I was trying to make is they solve a symptom not the problem. I used UNI foam filters in the CB cast aluminum housings and they were an improvement over the exposed paper filter until water was added to the mix. The dirt was washed straight through them. This is easily verified when you remove the elements to clean them, The top of the carbs under the air filters will be covered in dirt.
So the opinions I have expressed are my own, right or wrong. The only fact in my observations with my buggy is after switching to the Donaldson set up two years ago I haven't pulled the idle jets a single time, and I don't have jet doctors. So your results may be different, In fact no one I know except me runs paper elements either they think my set up is ugly. So I get to enjoy a cool beverage while they stop to blow out their idle jets. LOL