Check this out.
http://www.edmunds.com/insideline/do...ticleId=105699 Basically the only way to legally import skylines anymore. I'm fairly certain that the skylines imported by motorex are no longer legal because of what the company did. Anyway, if that process can work for a skyline it could probably work for a E46 ti.
However, it will obviously be expensive because you still have to modify the body to comply with US standards. But, you effectively turn it into a kit car.
I do know of one individual who was able to legally import and register an Audi S3 into the states, he got it from Mexico (and promptly drove it drunk and totalled it, but thats another story). He would never say what he had to go through to get it legal in the US but he did make it sound like a very complicated process.