there are a myriad of regulatory differences, they have been lobbied for HARD by the existing large automakers. They claim to be for safety, however in reality they are 100% about protectionism with not even an afterthought to safety, unfortunately because they are "safety rules" you can't fight them the way you can protectionism, it's quite frustrating.
That said, here is a list of the things that COULD be different on the two models that would actually be an issue at the border:
- Daytime running lights, this is obviously just a matter of loading the right software, shouldn't be a problem, can also be done aftermarket very easily, even on a Tesla.
- 5mph bumpers, I find it highly unlikely that Tesla is making a different bumper for the USA vs Canada, but even if they are, swapping bumpers is not impossible
- immobilizer, Both the USA and Canada require them, however the Canadian one must arm a few seconds quicker than the american one. I bet that the same software update that would fix the DRL would fix this.
- child seat anchors (yes, even if you don't have kids), Canada requires stronger child seat anchors (ridiculous really, as the force required to break an american one would already turn your baby to soup, so I don't see what making them stronger helps) Again, I find it unlikely that the Canadian and American vehicles have different ones, however aftermarket ones are easy to come by.
There are other regulatory differences (like the colour of seat belt buckles) but those are not checked at import and would not cause a problem.