Sorry to bring this from the past, but I went out and under my KJ, and only the rear of the differential changed, the front has the same 3 point attachment and the only change is the rear attachment, you can see the pictures of both differentials in this tread
http://www.jeepkj.com/forum/showthread.php?p=352794
And I think that the rear attachment can be made, cut the a little to the rear of the cage, it already has a cut under the diferential and put the KK diferential with all the options, now the real question is, can you run bigger tires with the KK differential? at least 33 will be ok for the investment and problems that can be found.