1) Moving car from Canada to the US -- just did it
Just want to share my experience moving my car from Canada to the US because this ended up being much easier than expected, particularly after reading many feedback / articles saying this would be a kafkaesque process.
There are basically 3 forms to prepare before going to the border:
Homeland Security / Custom form ; this also requires a vehicle registration proof (that varies from where you are in Canada ; in BC, the ICBC registration for instance), assuming you've had the car for more than 1 year.
EPA form - assuming your car already has an EPA sticker on it ("Vehicule Emission Control Information"). You can find it under the hood. Mine had it, so all good.
US Department of Transportation form - you car needs this other sticker from the US department of Transportation (NHTSA). My car had the Canadian equivalent, so I had to email my car manufacturer and get a letter from them certifying it was US compliant. Took 48h to get the letter via email.
Then you get to the custom, ask to import your car. They redirect you to secondary inspection. At this point, you need to show the 3 forms above (and supporting documents). I didn't call in advance and did this on a Sunday. It took an hour, and I felt I sometimes knew more than the officers so just make sure you have the above and you should be fine!
Next is to:
get your car insured
go to the DMV to get the car registered, with the above papers
My take: most cars in the US and CA are similar, all made in Mexico (??) so they are made for booth US and CA regulations, though they may not have the right stickers on them.
NB: This was the best resource I could find: family.lovetoknow.com/vehicles/can-i-take-my-canadian-car-to-the-us-to-stay