Just by converting over to a redneck version of a dual intake, WGDC dropped 2-3% for me. e.g. 84ish % iirc to 78-82% rpm dependant in 3rd gear now.
EDIT: I will throw in some more here to explain how the engine works in relatively simple terms. As of late I've been dealing with some issues that have made me delve a bit deeper, than I had in the past, into the control systems.
The control systems for the engine have limits set into them. The computer system in order to satisfy the drivers requests, looks into what driver is asking of the system to do. The short version of this is when you put your foot to the floor the computer sees you want everything from it. This is called a torque demand. Now the computer sees this torque demand and excluding available traction and drivetrain limits that are set, calculates how much air is necessary to meet that torque demand. Now if your limit is set at say 600 ft pounds of torque it will work to supply enough air to achieve that.
It takes so many pounds of air to burn so many pounds of fuel.
There is also a boost pressure limit set in the system. As long as you do not exceed the Boost limit the computer will add as much boost as is necessary to supply the requirements of the torque demand. This is called an air demand. So if your wgdc is dropping, you're more easily meeting your air demand.
In my case not only is my wgdc dropping but so is my boost pressure due to air demand being met more easily. Unfortunately I've been experiencing other issues that I'm hopefully soon to rectify. Anyone else care to chip in and correct any mistakes I might of made here?