Documents you may need at the US customs office are - ITN/AES number (which you can apply online, see above post), email to the specific port with the ITN number, title copy, etc (check that port requirement or call them) 72 hours prior and print a copy of the confirmation reply, original title (most imp), vehicle registration, bill of sale (if purchased preowned, optional if you have the title), ID proofs
You can check RIV website -
https://www.riv.ca/VehicleAdmissibility.aspx if your car is eligible. In fact, they have a full checklist and process mentioned for importing the car.
Make sure to get a recall clearance letter from any dealership corresponding to your car.
I paid basic taxes for owning a car, which you have to pay for any car in general (around $300). This depends on the value of the car. I did not pay any import duty tax as this was part of my personal belongings. If you are bringing your car later make sure to put it in goods to follow.
If you have a decent car, then I suggest importing your own car as it is cheaper in the US compared to Canada. Also having my car with me when I moved in was extremely helpful, as it was my only car.