So I hooked up the IAC hose to the plenum, and the good news is that the car doesn't completely stall out after load (while in neutral not moving)... also looking over the original cross over or J-pipe on the stock RB25 Manifold, I think the big bung/pipe is for the IAC... so most likely I'll just run it like it is for now until I can get the bung welded BEFORE the throttle body.