Hi Cooky,
Its true you wont pay US sales tax but you will pay 5% Duty on the kite and 10%GST on the kite,duty and postage when it gets to AUS.
If you buy your kite from overseas the Aus distributer wont be able to help you with any support or warranty issues as they keep a record of the kite numbers.
The prices didn't look so hot to me, a lot of old kites too.
eg- 13m 2005 SS Fuel.
Thier price- $1470.69
+ 5%= $1544.22 + 10%= $1698.65AUD
Current price for 13m Fuel in Aus is $1450

Id suggest speaking to your local shop and asking what specials they have or what price they are selling the kite you are after. If they have a website they may not have thier prices up to date.
Jason
www.briskites.com.au/