The wreckers would have some good ones at a much cheaper price then a new one, but if that's no good then go to www.injectorsonline.com (http://www.injectorsonline.com)
Injectors Online advertise on this site so you can contact them at [email removed]
Here's their forum advertisement - http://www.calaisturbo.com.au/showthread.php?t=63708
repco do exchange ones through a company called injectronics. they come with a 2 year warranty i think but will set you back about $150-200. new ones are around $500 (don't buy a new one)
i have one, and i have the pod filter adapter thing for it too if you want to give the air box the flick!
http://www.calaisturbo.com.au/showthread.php?t=84316