I have imported about 4 aircraft over the years for my own use and have never been disappointed other than by the Australian side of the transaction ie. Assembly, CofA, instrument changes etc.
If possible get the instrument changes done in USA, much cheaper.
You will need an Export CofA which is basically an annual inspection with extra paperwork.
If possible do the container packing yourself because other people don't care about your stuff.
Go to the US and inspect yourself it will be well worth it.
Don't ever import from any other country than USA, UK or NZ unless you really know what you are doing.
BETTER STILL DON'T DO IT ....IT IS ONLY MARGINAL FINANCIAL GAIN....YOU DO IT TO GET THE MACHINE YOU WANT NOT THE PRICE YOU WANT
If you do do it make sure you insure the container for its true Australian value.
Make best use of Escrow.
Get the seller to ferry it to the point of disassembly.
Do not let the heart get in the way it is a business transaction, do not part with any money until proof of completion of each part of the deal can be confirmed.