Shipping kills to Australia., specially from US. Add to the exchange rate your not really gain much nowdays.
Ive Used AMS once, but freight cost more that the part.
Theres a couple good Ebay vendors from Germany and England which can get most parts if you ask and freight is well priced but slow.
Depending on what you want, places like BarginBikeParts and Alessi have some stupid good deals at times. (eg: termi slip on $900, rear bag $55, Termi headers $699)