And it should have ended with the link to the parts diagram, but not so fast. I'll put together a write-up to add to the brake booster line thread after I solve this, though the part is NLA or has been replaced. Biggest issue is that the new one separates the coolant junction with sensor and other coolant hose connections from the brake booster line connection. All I need is the brake booster connection, but as you can see in that diagram, it shows how part 7a goes into 7b with a nonexistent connector.
That part is the one I referenced at the start of the thread, which appears to be #10 in the following diagram, which doesn't have the pass thru connector for the brake booster line like the original. The part linked above in ECS tuning does not fit the BPY 2.0T FSI engine in my 08' GTI.
So much brittle plastic in here is really making me loose interest in wrenching this car, but I need to get the vacuum assist connected back the the brakes.