You do realise that Luxury Car Tax is 25% don't you? And you have to add shipping to the cost of the car before you add your duties and taxes. By your calculation, Luxury car tax comes to $22,447
Car Cost: $72,381 (which is optimistic on it's own as you wont get 84yen when you send money to Japan)
Shipping: $1,825
Combined Total: $74,206
Import Duty @ 10% on combined total: $7420.60
New Total: $81626.60
GST @ 10% on New Total: $8162.65
Total before Luxury Car Tax: $89,789.25
Luxury Car Tax @ 25%: $22,447.30
Therefore you're looking at roughly $120,000 before on roads.