ok this is the first part of your air box mod, were there is blank space there used to be a white plastic piece covering the whole inside. you want to take that out. im sure you can figure it out easily its not hard.
this is what you do next, this piece you need to take out of the location its in. where the hole is there was a silencer you want to take that piece out. toss it or save it what ever you want. but the hole it was it you need to make bigger preferable as big as the hole that is on the frame. use a sawzaw or something of that nature, I couldn't find mine so I had to break my fingers using a hacksaw to make the hole bigger, that didn't work as a i wanted it too.
once you get both of those steps you can put the box back together, then to the next step.
This is the hole where another silencer goes, Im sure you've all seen it, but I didnt' want it there anymore, and I didnt' want to leave an empty hole because I was sucking up dirt and all kinds of stuff, so I took a cap from a model spray paint can and put it in its place, i had to force it a little bit in ther but it went in and well I have no probs. so thats what I would suggest, one its black and not that noticable so... but there ya go, thats how I did mine and wow can i tell a difference.