You can freight wheels via EMS as long as they are relatively close to 10-11kilos each which is about the weight of a standard 33 GTR wheel. Each wheel is shipped individually or if they are light enough (<10kilos each - not real likely), in pairs.
See freight is significantly cheaper though.
Duty is 10% of the wheel cost + freight cost
GST is 10% of the wheel cost + freight cost + duty
So by air, at say 11kilos each EMS will cost you 16,200 yen per wheel or 64,800 yen for all four.
Add the 21,000 yen per wheel (for example) so 64,800 + 84,000
Add duty of 10% of that (14,880)
Add GST on top of all that (16,368)
Total = 180,048 yen
At todays exchange rate of 87 yen per 1AUD you will realistically see 85yen exchange rate from banks so landed you're looking at $2120AUD.
At this cost you are looking at customs issues and you are going to have to use a customs agent to get the items out of customs. Add another $70 for a customs agent to handle that for you.
If you look at the same example posting by sea (7,450 per wheel) the total comes to $1620 before customs agent fees. Bit of a wait but a good saving.