Finishing up on my SR swap in a 92 hatch. I running an ARC smic and the original T25 but this is my first turbo car so I'm learning as I go. Unfortunately hard to find info on the stock set ups since most stuff seems to about front mounts. I just wanted to verify where these two lines go off the intercooler.

I have an apexi intake on the way, I assume the large line plugs into that. The small hose appears to come off the stock BOV, where does that go? Amayama parts diagram shows I have to run that all the way over to the throttle body. That seems like a LONG way to go but is that correct? It also shows it T's off to an unnamed discontinued solenoid. Is that solenoid needed? I'll be running the wastegate directly to the charge pipe for now until I figure out the boost controller situation.

Ok, think I have it figured out after jumping multiple forums. Bottom line on tb with arrow is positive pressure only and should be capped off. The top left tb port goes to fuel pressure regulator and optionally a boost gauge. Right tb port goes directly to the small port (BOV) that I labeled "throttle body". Did that, running the vacuum hose along the front of the engine and then down the side of the fan shroud that had a handy clip built into it that the vac hose ran through nicely.

I can apparently run the wastegate directly to the cold pipe (post intercooler) charge line although there's tons of back and forth about whether it should be on the hot or cold pipe. My cx racing smic piping kit only has the port on the cold line so I'm stuck with that. A boost controller can be run in between that if wanted.

Found no mention of that mystery solenoid. I'm guessing it's the one that is on the bracket that the igniter chip goes on but the diagram I saw showed it on exhaust side of the engine, not on the intake like I believe that one is mounted.

So I guess the last thing is that large port that I assume goes to the intake that's on the way. Any confirmation on that?

Glad you got it (mostly) figured out.
Wastegate signal can be run to cold side, hot side, or even from manifold pressure depending on what you're looking to achieve. Running it on the hot side or cold side will tend to leave the wastegate open a tiny bit longer during shifts and off-throttle events while your blow off valve opens up and takes over. The hot side generally has a slightly higher pressure than the cold side, so if you don't have a boost controller and want a little less boost, run it on the hot side... the most boost would come from the manifold signal and accounts for all pressure losses across the system.

I'm not familiar enough with SRs to answer your other questions, but we might have a diagram or 2 in a factory service manual. Have you tried looking there?
https://www.nicoclub.com/nissan-service-manuals