Also with how things are going in the Industry. You will need to buy the! HPTuner software and self tune. All of the commercial tuners are going emissions on tuning only now in light of the crackdown.
I concur.Why even touch the internals? The 6.7 improvements will increase how much cylinder pressure the engine can take and more fuel on tap. You will not be able to change anything on the drivetrain until tuning arrives. HP tuners will likely be at the head of the game in building the software. If your planning on really building one of these engines I hope you have deep deep pockets. Since it is not a new engine there is alot of info on the 6.7 out there and how to build them for big power.