well as for quality i have only had mine in for about 6 months, no problems yet either with sagging or with anything else... as for customer service, i haven't had any problems in order to need it yet so i can't really comment...
all i know is that they do ship to Canada, or course it isn't cheap mind you.... their 3" full spring pack kit is $418 or something USD, they charged me $175 USD for shipping (i live in NL)... then i got nailed with $120 CDN for duty and brokerage, i believe the package was 116 LBS though.... if i remember correctly it was like $830 CDN for everything to my door... i placed a phone order aswell