Okay, I have done it, and I agree best $30 spent. It has better pickup, but not only that, you can hear the intake roar when you give her a bootful.
I took pictures of what I did, so when I get some time, I will post mine up here.
But in the process, I didn't end up using the pipe joiner that came from Holden, I just used the sealer foam and the shroud, The Big hole on the left hand side of the air box if you are facing the engine, was a good fit into shroud, with the foam around it, sealed nicely. Then I cut up the air conditioner "charge" pipe, used the straight section of that pipe for my second hole. Looks a treat. Then I have to cut a slot for the conduit to fit down into, to allow the connector for the IAC valve to go through, drilled a 32mm hole for the IAC sensor to fit through the shroud. It was worth the hassle though, I will post pics later on.