As for not going muddin or through water. Thats B.S. I have riden sport quads for several years now and I run nothing but a K&N filter. I get into more mud in one ride than your air filter will EVER see. Just when you clean it let it dry completly then spray an even coat of K&N oil on it. Let it dry and install. Clean your filter often.
Dirts for racing and pavements for getting there!