Originally Posted by supershaft
That picture is a perfect example of a K+N filter not fitting right (it's bowed back in front and unfiltered air and nuts are getting by for it). The trouble is that in my experience once they have been bowed back like that there is no fixing them. The rubber gets a memory that keeps bowing the filter back even after you cut into it to allow the filter to slide around the starter cover thusly letting the front lip fit over the front of the box like it should be.
Square airboxes? Personally I like them more than clam shells. Easier to work on and they work better IMO.
Agreed, I changed that filter the first day I cracked it open - after removing the bottom box and starter cover etc to fully clean them all out.