It's not true dual if you have a Y pipe since the Y is combining the exhaust from the 2 headers into one pipe.
Can't tell you for sure on performance between the Y and an H or X td setup on these trucks but in my opinion unless you're drag racing your truck, a good flowing Y pipe set up will be enough for performance.
12 Ram Cummins - MB Motoring Predator 18" wheels with cheapo 33x12.5s, full tint incl windshield, Pioneer double din, DBALL2 remote start. Coming soon: Better tires! Smarty Jr with full deletes, 2.5 leveling kit
99 Trans Am LS1 | 1989 Suburban 2500