I pulled that stupid sound tube today on my GT. What a colossal pain in the ass. There is a nut on a stud holding the tube in the firewall. Nearly impossible to get at as it is behind the drivers side cylinder head. I did get it out and plugged the holes. No electrical anything so it didn't throw any codes which is as expected. Honestly if it made any difference in the sound I didn't notice but it sure cleaned up the engine bay on that side. That had a cost Ford a pretty penny. There is three chambers, two could have some kind diaphragm thing going on, three or four rubber sleeves, and a bunch of clamps. Why couldn't they have put that money to better use like making the shiny shit match in the interior.