As to passing emissions, a free-flow cat (RANDOM TECHNOLOGY) and a mandrel-bent 3.0" single exhasut won't give up enough power to matter. But the cam in the 380hp version requires a lot more numerical gear and may not be at all ideal for running power accessories. Torque is the only thing that matters above 4000 lbs. Does that transmission/driveshaft/rear axle/suspension have the guts to handle it is the question I'd be asking about this swap.
Rule of thumb for converting gross to net is deduct 22-25%.