Platinum,
I had one of those too, It either seemed to work or not work, I couldn't tell much difference if the gun was tuned for 100% reliability. If you took to much gas away, the gun got softer but reliability suffered. For a 16' gas system the pigtail makes it act like a 20' gun with similiar cycling except you have more pressure to run your comp in the shorter barrel. Also when installing the pigtail you are advised to drill the gas port open to allow more flow, mine may be drilled a little small for factory loads but this lets you adjust the flow. You could use both and you might really have somthing neat.