Goods over $1000 attract 5% duty this is added to the value of the item including postage then 10% GST is applied to that (tax on a tax) so in reality you end paying around 17% extra that's the way I read it on the customs website.
Using USPS i got taxed... using fedex i didn't.. have used FedEx 4x since January, and everything has arrived without import duties.. each item has been at or above $1000