I have one of these bad boys in my car and it's performing pretty great. For some reason, when I first installed it a couple months ago I used the stock vacuum line that I had for the intake. (If that's what the thing is called that plugs from the engine to the intake piping.) Anyways, today I saw the pictures on the site and realized I was supposed to use the one that was included with the intake. I always thought that was a cover and used it today. I noticed my throttle response all of a sudden got slightly better which is great. However, I noticed there was another hole on the piping similar to the vacuum line piping except that its smaller and has a cap on it. Is anything supposed to be plugged in there? I was looking on the installation instruction pictures and couldn't see it that well as it was a very small picture.