Break as much ground as you like, no diesel needs to dump boost when closing the throttle because they don't have throttle valves, the full inlet charge always goes into the cylinder.
Some diesel drivers might want the sound of a dump valve. For those, the Forge thing will deliver it. It will affect the engine's performance in a bad way. I don't know if anyone has kept one on long enough to tell if it will damage the engine, but it is a distinct possibility.
It's a cosmetic accessory. Hook it up to a cylinder of compressed air, at least that way you'll still have the boost you need.