In theory ... removing the Duel cats on a 2500HD 6.0L would that improve exhaust scavaging??.... and if adding a X pipe would you add One right before the Muffler or right at the point where the passangers side cat would have been because thats where both 3"pipes equal out in a straight run towards the duel in and duel out 2505 flo pro muffler duel 2.5 leaving the flo-pro