Boxhead,
Towerhobbies is a great store. I have bought all my radio control plane stuff from them and save heaps. They are very international friendly and packages arrive to sydney in about 4 or 5 days. Hobby shops here just charge way too much.
Strida, i bought my wheels from Wheelboyz in QLD. I priced getting them from the states and wheelboyz were only about $100 more without adding the duty and GST which i was uncertain on the amount.
Depending on what type of wheels you are after its worth calling them. I got a good price on custom offset American Racing wheels sent to sydney. I got the torq thrust wheels, but they also have a nice looking cobra wheel.
www.wheelboyz.com