I picked up a 1/2" on off of Ebay for $20 shipped. I'm not planning on taking it to the dyno to see the difference but if it helps a little great if not it doesn't hurt. In retrospect, it does help probably very minimal, by adding volume thats present in the intake manifold. It is not worth it if your going to buy one for more than $20, like some people i have seen want around $60 for theirs and its not worth that money.
Good Luck, hope this helped.