I have a 13 manual JKU and recently put the drop-in into my vehicle. I went from 16.9 mpg around town (leveling kit, stock wheels/tires) to a steady 17.5-17.9 without even trying. About the same on the highway. I just like it because I don't have to replace the filter all the time. Just re-oil and clean it and I am good to go. This thing won't ingest any more dirt than the OEM filter. Don't know where that info comes from. If anything, the oil tends to trap those pollutants. Just make sure you clean and oil it regularly. The stock white filter is dry and is certainly not as efficient doing that. Same thing when you put too much oil on a bike chain or on a firearm. It grabs and holds dust and dirt. Granted, that can be detrimental to items like those, but in the case of the intake in an motor, it's a positive.
If you buy an air filter hoping for a dyno improvement or major HP gains, you're buying into the hype. I slapped a JWT Popcharger on my 350Z years back, thinking I'd get 12 hp as it claimed, and I was disappointed when I saw a .3hp gain. LOL. Maybe if you coupled it with a hi flow exhaust, maybe.