After having the chassis that just set the record at the ring and from a pure cost/business perspective, I find it hard to believe that Dodge will come up with a new frame, tranny, rear end, or major suspension changes. We also have world class brakes - so I doubt they change much there either. It would also take a significant increase in cost to really shave any weight off - so I don't see that happening.
I could see a change in the windshield angle/design and doors which would change the overall look and hopefully provide for some more headroom. There was some early discussion regarding the Fiat Multi-air system - so maybe that is how they achieve the HP increase without having to make huge changes to a proven engine. Traction/stability control has to be a good thing with a motor that's pushing out 675/600+ numbers.
Gotta hand it to Dodge for being able to keep everything under wraps for as long as they have.