as stated above they are stronger made cases but the bigest difference is the converter dust shield the k cases sheild is thick aluminum that had strut rods that went from there to the motor mounts that stiffen it sothe bellhousing doesn't crack.
without all of the pieces theres really not alot of difference between them. almost forgot theres also a strut rod that goes from the transfer case to the pass motor mount.
also the dust sheilds won't enterchange between the two.