The resonator muffles the sound of your intake. It also makes the atv quieter. It changes the sound of your exhaust as well as make it loader if you get rid of it. If you get rid of the stock airbox or manipulate it, then you might as well get rid of the resonator anyway because now its no longer of any use.
To answer your question, in my view it is worth it to get rid of it. If anything it is more restrictive then just a straight pipe back. I would not get rid of it with the stock pipe though..it was designed for it. B)
