Its not needed but I do recommend it. It will be running on the lean side if you don't use one and it will cause it top pop on decel and hiccup at stoplights when you go to take off from time to time.
To tell you the truth, its best to get you stock ECM re-mapped, but I don't know if that is possible for you over there. Dobecks and Race ECM's work great. The ECM would be the easiest because all you do is plug it in and reset the TPS and you are set. The Dobeck you need to set up and tune some.
Just let me know what you want to do. I will help out in any way that I can. I can ship you an open airbox mod too if you would like.