There is an arguement to be made that these are turbo'd trucks and it makes a difference... but with that said...
We have used K&N's on our race truck for years... and it is a high compression race motor... 500+ hp from a V6... and we have never once had a problem with dust in the motor... nor have we ever dusted a motor.
Most of the people I have heard of that have had a problem with the K&N filters are those that have ran the filter element only... using the standard Ford airbox... The standard F0RD box is the problem more so than the element itself... There are stories of guys dusting a motor running paper elements as well with a factory airbox...
I have had a K&N FIPK on my 99 from the 60,000 mile mark on the OD... I still have one on there ... now at 165,000 .... My 99 has been a pit truck since I purchased it... I use it for chasing the race truck... I use it in the dustiest/siltiest enviorment that any truck will normally ever see.... with the exception of the actual race truck. WI have never once had dust on on the other side of the element...
To give an example of how bad the silt is.... Silt is like talcum powder, it gets everywhere.... I had to go recover the race truck one time... it was approx. 1.5 miles from the paved road down the race course... I had to wait until the course closed so I could go backwards on it to recover them.... anyways, the course had been raced on all day... the ruts were 12"-18" deep.. if not deeper in spots... the silt was over my knees deep when we got out of the truck...
The rear hub assembly had been ripped off the truck and there was no way to move the truck except to drag it out.... I hooked on a tow strap and drug the truck back out the 1.5 miles... the added load and as deep as the silt was .... it was going over the top of my truck like water does when you go through a puddle at high speed... I couldn't even see... I kept on course because the truck couldn't get out of the deep ruts... about a mile down the trail I lose all power and the truck is blowing a cloud of smoke like a freight train... When I stop and let the dust settle, I open the hood and find my cone style element is squished up like a twisted tin can....
I knocked off as much silt as I could and stretched the filter back out.. put it back on and pulled the truck the rest of the way out... loaded the race truck on the trailer, and then drove back to main pit and then back home... 225 miles away... when I got home the filter was covered in silt ... I removed and cleaned it... checked the pipe leading to the turbo for any silt that might have made it's way past.. it was clean...
I'm not saying that people have not had problems with K&N's but I believe there are other factors in many cases..
Would I use a K&N element filter in a factory airbox --- no
But i wouldn't hesitate to run a K&N FIPK on my truck.. my 2002 has one also...