Just came from the dealership with the check valves that I ordered on line. Went to the parts counter to get a printout of the $400 price that everyone, including me has been quoted and to my surprise the valves are now $24.75 each. I had him double check and that's the correct price.
I was going to point out to the manager the price difference between the two countries but that shut me down pretty quick.
You may get them cheaper if you have some sort of discount but I don't know that it's worth the hassles of ordering them from the U.S. now that the price has come down so far.
Just walk into the dealer and pick them up.