best air cleaner to use?

I used to run a K&N filter. I don't any more. I stay as far away from them as I can. I had grit on the inside of the air filter assembly of my dune buggy. I figured it was leaking past the filter somehow. After trying a lot of different things I finally realized that the grit was going THRU the filter. Yeah, they flow a lot air. They also flow some amount of everything else and I don't need that in my engines. Granted, this an off road application, but that experience soured me on K&N's. Don't use them, don't like them, & can't recommend them in good faith. May as well just run some stainless mesh for all the good they do.

BTW, Using one on a Cummins voids the engine warranty.

I use fully enclosed filter cans and duct them to a cold air source. They're Fugly, but one of the best (if it'll fit) is the filter can assembly used on the GM 6.2L diesels & carb'd 454's in one ton trucks. They enclose a ~5" tall, ~14" OD filter element.