This would be such a headache just for heated seats. I sympathize with your desire but it is not worth the trouble. You would have to find a dealership willing to violate the franchise agreement, then modify the car to hold up to the slightly different US regulations, then ship or drive it across the border absolutely dirt free (no foreign dirt allowed at the border for imports) then have it inspected and pay the import and US taxes at registration... Oh man... And good luck having your warranty honored.
There are all sorts of hoops in place at the border to make sure this process is unappealing. It's such an unattractive process that my brother who lives in Boston left his car in Canada when he moved and is leaving his car in Boston when he moves back next year. He drove a base model civic in both countries.
Yeah that all makes sense. I do miss having heated seats. I don't really like the "heat pad" option. Maybe The dealer could just install the needed hardware into the current seats as an "aftermarket" option? I know when I was shopping for a Mazda 3 for my wife, I wanted the base trim but the only thing it was missing was the heated seats and they said to just bring it in and they could install them for a price.
Then again the higher trims had them so it was readily available for them *shrug* I'll see whats possible, for now I'll enjoy the summer months