You can save your money while stationed at Okinawa so when you get back (~4 years) you can buy the stuff you want for the car. Another bonus while waiting is newer products will come out during that time (be it engine, brakes, suspension, you get the idea). Just stack that money and wait till you come back.
With all that said and you being stationed in Japan, see if you can buy/drive one of these. They are a real kick in the pants. I used to own one :twisted: