600hp is pretty stout for a driver, but you should be fine with the 14 bolt with no more than you plan to do.
I ran 42's and 44's on my 1/2 ton stuff for years and would break a front axle every now and then. (And I've always been pretty hard on 4x4's :wink: )
I switched to a dana 70 rear and dana 60 front and it added a bunch of weight to my truck. Not to mention had to get different wheels too.