It doesn't have to travel that far! It is part of the Wastegate. If you look at the picture, it goes from the top opening of the turbos (the valve is attached to the left side of the turbo) to the air hose(#4) into the charge-air cooler.
I received all my parts Friday afternoon. I was going to write a DIY for it, but I didn't see much interest on the subject so I just put everything together. Everything is working great again. I erased all the fault codes, ran ISTA again, and I have all green lights
. I can feel the turbos getting more pressure and faster response. According to a description on ESC Tuning, the Wastegate actuator releases excess boost pressure. A failed unit may result in a boost leak, reduced performance, and, ultimately, turbocharger failure.
I drove the X6 for over 50 miles, pushing it to the floor. No more limp mode after fast acceleration!