As you all will notice from this post, I don't know much about engines. I am attempting to do the free WAI as posted by Altima2002. I bought the K&N Air Filter and some duct tape. In Altima2002's picture of the engine, there are two silver boxes on the right hand side, one with a hole in the front, and another behind that, which has a tube going from there. Which one is the air box, and which is the air filter? I am assuming you remove the front one to find the whole that you tape the resonator at, but where exactly does this new K&N filter go? I guess a better question is, where is the old filter that I should be taking out? As much help/detail as possible will be appreciated, I don't want to mess anything up.