this might be a stupid question but i just recently removed my aem cai and wanted to go back to my stock intake. i used the k&n filter that was on my aem cai and attached it to my stock itr intake arm. the filter itself has a long rubber neck that is 3 inches so it fit fine into my intake arm. it also fits good into my airbox but the question here is that the filter is not long enough. does it need to cover the whole airbox like a stock filter does??

 

your fine the way its set up it does not need to be the entire length of the box

 

As long as the filter is fitting into or over the arm itself you'll be just fine.

Brian