I found the answer to my question on Sideshows website. Now I can breath a sigh of relief.
Sideshow chooses to ship all Canadian packages via FedEx International Economy Air. Economy Air Service will provide quicker delivery than the previous ground service - in most cases allowing our customers to receive their packages 3 or 4 days sooner. Canadian customers will also be able to track their packages via the FedEx web site. Customers can call FedEx directly to inquire about the additional Canadian duties and taxes, such as the GST, PST and / or HST, that are to be collected at the time of the package delivery.