I read a lot of reviews contemplating the same upgrade. However, after careful consideration I decided to stay with stock. The foam type filters seem to do a better job filtering. You would probably get a little more airflow with a K&N but to me it wasn't worth the risk. I've run K&N in several vehicles before without problem. However, I wasn't running them in the dusty conditions these UTV's will be in.Has anyone changed their stock filter to a K&N? I have used them in the past. If so any, problems?