Zenderm3, ask for tirerack to split shipping for you into two shipments.
I done this recently and to avoid customs, I had 2 tyres invoiced under a different name (family member but different surname) and sent to my home address and 2 tyres invoiced to my name and sent to my business address.
Shipping only worked out to roughly $100AUD more this way...
I dealt with Luke Pavlick, he was very helpful with splitting the shipping up.
I ended up getting the Yokohama Advan Neova AD08's. The seem great from the reviews/tests.