Ok let me see if I can remember how my box looked.
remove 2 metal clips. remove filter,
unscrew 2 screws on top using a 8mm I believe.
you should then be able to remove a middle section.
now notice how there is a 3 1/2 inch tube going from front through the middle section
then to the filter. the idea is to remove as much of that middle section as possible without damaging the outside housing including the 4 or 5 tabs at the bottom so you can put it back together.
then more air can get to the filter than just that 3 1/2 inch area.
I myself installed a FWI (fender well intake) and like it much better.
Im going to see if I can find a post with pics for you.