I've imported several VW's into the US from Canada. It'll have a sticker under the hood that says it complys to all US and Federal emissions and safety standards that were in place at the time of manufacture.
You used to have a bunch of paper work in hand for the border, you no longer need this. US Customs will take care of everything at the border crossing and give you a form to take to DMV, all you need is proof of ownership.
If you drive the car in Canada you'll have to get temporary Government issued Insurance. License Plates stay with the former owner in Canada, not with the car.