Importing a car from Canada

There are two papers to fill out at the border crossing when you return that they will provide, that's it. Just have the title and bill of sale. The car needs to be 25 years old or there is EPA issues I've been told, also it needs to have been made in the US or there may be a problem. I have bought a couple there a few years ago from Ontario into NY. Customs are usually helpful if you call, they just check that the vin and title match on reentry. More than 10k cash needs to be declared, do not hide it and try to go over, you may lose it.