Nothing goes in that "hole" in the back of the intake manifold. I'm not sure which vacuum line your talking about. There is one that comes up from underneath to the BOV.
You can use my car for reference if you'd like. I'm in VB...just pm me (again)
But I know I'm not the only WRX owner here !!!!
Whats up fellas !?!?!? Help a brother out...