What are your opinions on putting a K&N filter in your truck? For those who do have them, have you noticed any positives in performance, mileage, etc... Is it worth the investment? Thoughts? Opinions??

 

I've got one... No real noticed benefits. I does, however, seem a bit louder/deeper rumble.

Although I have had no problems with it...Would I do again? Probably not.
Would look into getting a dry performance filter. Have seen others with issues of Oil on the MAF (I've not experienced this but I am pretty careful to watch the amount of oil i put back on the filter when I recharge it)

Others will be able to give you more scientific data... i can only talk my experience.