I think the level of competition is ridiculous. You could name any of 20-25 drivers who have a legitimate shot.
This isnt the Petty "run what you brung" days.
But to answer the question. Is it even a question...?
Time to call him 6X
Front Row Joe as a Dark Horse - even that is a stretch. I like him, but with the competition, small teams can't compete over the course of 36 races.
My heart says Carl Edwards, and my head says him also - I think he is more upset than he has let on about last year. He is going to go even stronger this year - although I think he is going to go for more wins which could end up with less consistent finishes (wrecks, bad pit gambles, etc.).
However, if he makes the chase, then he may go a little more conservative at that point.
My Dark Horse is Marcos Ambrose - if he has decent equipment, I think he has the heart to go after it, and he has experience now on all of the tracks.