my k&n went right in , and is a little loud uphill, but her in fla we aint got no hills. i think they all give a little more airflow and a cleanable filter, and i have put a little air deflector to force more cool air towards the upper right fender area would like to see a before and after chassis dyno with any av club members truck and not some magazine article claim. K&n sounds good from 4500 to 5800 and i listen to it quite often!!!!!!