I just picked up winter tire package from Ogdensburg ( I purchased from Tirerack ), it was smoother than I thought, I spent 2 hours round-trip from kanata, $10 for gas(I drove my small car for picking up), $6 for crossing bridge($3 one way) and US$25 for ups( I had five packages), on border I did pay duty+gst+pst close to $200(if I asked tirerack send to home, I would pay US$ 177 for tax + US$70 for duty + US$23 for Provincial Tire Fee + US$30 for Brokerage Fee + shipping fee US$150 more)...
As nowhere001 said,
http://www.ottawatiresdirect.com/ have good price for tire and rim package, they have subset of tirerack choices, I guess that they are getting group price or distribution price from tirerack and they set up the sale price little cheaper than tirerack send to canadian address, but more expensive than you pick them up at border. Anyway if I only buy winter tire package( I did buy something else from US) and they have my selection, I would get tires from them instead of getting from US, because it only save up to $200.