I have had limited success in find options to buy parts in Canada however I did come across Ultimate Racing's website and even thought they only sell 3 direct fitment part for the Fiesta ST, they are located in Ontario Canada and make custom exhaust. This should help avoid any tariff/duty. Alone for the Fiesta ST I see 12+ options to customize the exhaust. Even the Downpipe have options. Again no affiliation other than being a Canadian myself nor have I ever used them.
http://store.ultimate-racing.com/collections/fiesta-st
http://store.ultimate-racing.com/collections/fiesta-st