Hi bud,
Shipping is not a issue , but it might be quicker to order direct from your local Ralliart dealer, it would cost around $74 delivered
the US part numbers are different to Australia's
but the part number for the Gearbox oil is 3717610 ( 4ltr ) , and its been re-packaged and translated to this "Diaqueen Super Multi gear oil"
it suites most Mitsubishi manual transmissions
I personally use this oil and also a few other VR4 owners with syncro problems, this can help the problem , but still might not depending on how bad your syncro is