I just replaced my original Mann Filters with the K&N's at 15K on the odometer.

The K&N lists much higher airflow than typical, but to be honest it was hard to tell if I experienced a significant boost, although mentally I felt good about it...

I'm guessing if your existing setup showed excessive dirt or airflow restriction, new K&N's would come shining thru.

My originals were pretty clean, but I changed them anyway cause I'm a fanatic when it comes to my cars...

(It really is a sickness...lol...)

Also remember, you buy'em once, and with good care and a recharge, I think they're rated for 200k, or was that 100k...