We had that satellite image at the factory some months back. There, with the help of GE measurement i concluded KJ600 was likely at least half a meter longer than E2C.
So, using 18 meters length for KJ200, i produced the comparisons below, which i feel are pretty good actual relative size comparisons.
The image on the left has those blue lines, those are the outlines of the fuselage. So it'd appear that not only is KJ600 longer but its fuselage is also at least higher (if not also wider, which is likely too) than E2's. Image on the left shows how much longer KJ600 is. Though keep in mind the angle of the plane is not identical, so KJ200 is slightly shorter than it first appears. (still longer than E2)
Other apparent differences, besides the obvious tail section, is the much bigger nose radome. Suggesting KJ200 might have a proper radar up there, and not just a weather radar like commercial airliners or E2 has. Different color at the tail might also suggest some kind of radome, but that's way too hard to be sure of. Certainly, there would be some benefits to having nose and tail radars. The main radar dish is fairly small and pretty flat. Assuming KJ600 radar also operates in UHF band, as does E2, then all those facts combined mean the vertical resolution of that main radar dish is abysmal, for modern standards. Which in turn may make it worthwhile to have some added radars with half decent vertical resolution. So once a contact is detected, the plane can briefly take a look at it with its other radars to get some further contact/tracking details.
Another difference is slightly longer engine. Whether that means a more powerful engine is impossible to say. But given that KJ600 does seem to be slightly bigger than E2D, one shouldn't be surprised if it's also heavier. (Don't know if E2D reused same fuselage materials/construction as E2C. Even if it did not, larger planes packed with new electrpnics still tend to be heavier, even if featuring more composites, than older, smaller planes)
The dish itself seems of generally the same diameter and position, relative to the plane.
Of course, all this is based on that image, not the the real plane. So if it's a CG or otherwise doctored photo, then we still don't know anything.