Need to look closer....
Top deck longer (with better fit for bigger lipos), Rear bulkhead is now split, F&R Bulkheads are now the same width apart, all chassis parts are mounted symetrically about the cars centre line. All these changes are aimed at improving the flex characteristics of the car.
Motor has been moved further back in the car to aid traction
New diff and centre pulleys (both bigger)
Improved diff (bigger rings, more balls, in-car adjustment easier)
Revised steering system
New (larger) hub bearings (1050 sized rather than 950).
Plus I'm sure numerous other improvements yet to be seen