My understanding is that you need to allocate plenty of time as most of the wreckers are not well organised. So you need to trawl through the yards knowing what to look for.

Then to get them into AUS, you need to clean them spotless to get them through customs. I know of one person who has done this a few times, and he puts in the hard yards to get what he wants.

Good luck with it, and let us know how you go. You might stumble accross some good treasure!