I had a look at the tiretrends site, and I think there are still substantial savings to be had by going the US route.
Even taking into account the exchange rate and the shipping, the savings by going to tirerack look to be at least $100 per tire....sometimes more, depending on the tire...plus, the selection is considerably wider, e.g., tiretrends does not sell BF Goodrich.
Just some food for thought.