I am going to try something different. I am going to mount a Uni Filter UP4275ST 2.75" ID x 4" in length filter into my 12 Focus while still utilizing the OEM air box.
Reason I went with the shorter dimension filter is that it will allow the filter to get literally a 360* of air...and now that air will also be drawn from the huge 6" opening in the front of the air box.
The filter length of 4" is used to mount the filter deep inside the box to prevent water from being sucked in.
I ran this same filter in my 06 WRX that supported over 400WHP so I am sure this will be plenty of filter for our Focus. It is also a dual stage filter so filtering out dirt is a breeze