Replying to Shipping

So I'm planning on ordering a few things off of Backcountry, but I'm from Canada, so as you probably know the shipping prices are pretty hefty. I'm being quoted for $49.35 for expedited and $56.44 for express. Obviously the express is more expensive because it ships faster, but for some reason I'm thinking it also includes the tax/ border duties, which means it will be cheaper in the long run. Am I right here? I'm in no hurry for my stuff to arrive, I just want to pay as little as possible.

So NS, what is the cheaper option in the long run? Am I right in thinking the express includes border duties and tax? Or would it just be cheaper to get the expedited shipping?