Australian member help please

I am looking for any member that can help me locate a standard Miata ring and pinion from Australia as they came standard on the 1.8 cars and ship it to me. These cars came standard with 3:63 differentials which is not available in the USA, I only need the ring and pinion but willing to buy the entire differential if needed. Please pm me with any questions.
Any help would be appreciated.
Thanks in advance