They changed nearly everything. I'm really curious to see them in action this week at IIC and hear reports from people. The '12 has been really good for me, especially with the thin chassis. I like they they went to 2.2mm, I felt like something between the two on the '12 would have been perfect.
I love the stability of the car, it's why I run an XRay. If they could find a way to have more steering from the center out without getting hard to drive, that would be the killer feature.