I run a K&N in my stock air box and its WORLDS better than any other filter Ive run, including a cone filter. I DONT drive in ANY dust, so that might be a difference, but Ill tell you, I gained 2-3 mph on the highway, the engine runs smoother, quieter, you can feel the power as its more responsive, etc. You couldn't pay me to use another filter while driving what I do, where I do. Even if you paid me AND supplied the filter, Ill stick with my K&N thank you!

 

I keep hearing the K&N oil filters are worthless filtration wise. I always use Wix since all of the older members i asked about it recommended it (I love how the tag for that emocon is smartass)

 

One of my all time favorite Cherokee 4.0 air filters is STP year 2007-2008 vintage. Whoever was making them, put a metal bar down the middle(long ways) and used more rubber foam that made for a very durable unit. I have one in my 99s 4.0. I have tried K&N, Spectre, Fram AirHog, Fram Washable(A Good filter 2007 vintage) panel filters along with ALL the paper filters at one time or another, and couldnt tell the difference between any of them. Except maby a slight Intake noise, with the cotton gauze(K&N, Spectre, Fram AirHog) like you get with a Cone filter.

 

I use paper filters in my 84 with the GM 2.8V6, my 87 with the first year 4.0, my 96 and 99s 4.0s, and my Beloved SilverStone Metallic 2001 currently has a FRAM Washable, which I will change in the near future to paper.