Yeah with the air you need to open these trucks up a bit. instead of compound turbo charging parallel would be better (one turbo per bank of cylinders).
what someone needs to do is release a whole new intake manifold and there is only one company I know that could pull it off.... Banks.
But they love the piston cracking good time that the duramax is.
I'm aiming for around 600 HP I see laughing gas and meth in my future.