Why the hell would you want to transfer your cars over? IT'S A DIFFERENT GAME.
This is another point that I forgot to make earlier. It's a new game, you shouldn't expect to be able to transfer your data over from the previous title. Like others have said, imagine being able to transfer your prestige level from a previous Call of Duty to a new one. There would be nothing to do in the new one in the form of completion. It would already be completed in that sense. It's a new game, you should play it from the very beginning, that's how I look at it. And that's what I look forward to.