first of all, shame on you looking for noise not even asking about performance. Don't rice out your Nissan man (not saying you are), be proud.

you cut the bottom of the box off while keeping the edge with the clips intact, then you switch to a K&N cotton filter. this modification on my car (nissan 200SX) is said to produce the same HP as a WAI. on your KA engine it should be about the same. 3-5HP increase.