I have all lengths and make of g36 models and the K is my favotite. Its in the Goldie locks zone as its not too big and not too small. It isnt all flash and bang like the C nor does not give up all the ballistic performance that the C does. The C is dead sexy like a super hot swimsuit model but they K is more like a beautiful woman who looks good, whos company you enjoy, and you can have a meaningful conversation with. Its almost a nice to shoot as the E but more handy and almost perfectly balanced.
If you dont go with an E and dont want to sbr it then do the brace thing until brandon directs the ATF to outlaw them.