Not looking to remove the system as mine is external but my explorer gt-40 setup is internal and im in the process of hunting down a rough idle so today I removed the upper just to see if it was possible for exhaust gases to enter the intake stream. Since im not using an egr spacer the egr tunnel dead ends at the back of my throttle body elbow flange but it appears that even though it dead ends that passage is not airtight and I fear exhaust gases may have been getting either inside or outside the elbow. I was able to blow a small amount of compressed air and it was escaping at the elbow end. Im going to figure out a way to block it off. I did notice a small protrusion on the flange mating surface just below where the vacuum tree screws in at, it almost looks like it is a consequence of when the trick flow elbow was manufactured, its smoothe but like a small dimple.