Use a mail forwarding company (as I've done, and as I've suggested a few times).

You could even get together with several other people who also purchase items from the US and would prefer not to use the GSP, and set up or use one mailing address in the US to which all parcels will be sent. Consolidate the shipment. You'll have perhaps 60 days before incurring costs for storage, so use that time wisely and buy those rare items within a 2-month period. Then have all of the parcels delivered in one shipment. (Mine come by FedEx courier; other forwarding companies may use different couriers.) Everyone involved chips in for the overall shipping cost. Everyone picks up their own parcels from the Australian address to which the items are delivered (or pays for those items to then be redirected to them/sent by the receiving person).

I have never had any issues with items sent to me by either US or the UK parcel forwarding company I use - and some of the items were rare, costly, fragile, delicate, etc. All arrived safely. Overall cost is worth it if you ensure you have quite a few parcels in the shipment.