Complete Belanger system is loud and will drone a bunch while cruising. The Corsa system is loud too, about the same on the DB meter, but does not drone at cruise.
A few of our guys have tried the complete system and switched to Corsa to remove the drone.
I'd stick with the Belanger headers and Corsa Exhaust. Lou can set this up either way.
A few of us have found hp to be about the same with a slight bump in tq using the Corsa.
Dan