OK, this is gonna take awhile! In order.........................
I have browntop injectors........I'll send you a PM.
The computer is inside the car. It's behind the passenger side kick panel, below the glovebox. Remove the kick panel and you'll see it. Look for the number LA2 or LA3 on the paper tag. It's easy to see. Here's a pic........................
You have to repin the Mustang computer connector. Sounds like a daunting task but it's really very easy and simple. Then your new computer plugs right in. You don't need the harness. Your Mustang harness will work.
Remove the VAM hose from the T3 (arrow) then look inside and you'll see the impeller wheel. Grab it and give it a good, firm yank testing for in/out play (remember you don't want any) then test the side to side movement (should be minimal).
Grab the radiator and resell it! Get everything you can!
You don't need the BAP or BARO sensor (Barometric Air Pressure). Your Mustang should have a MAP sensor (Manifold Air Pressure). Simply remove and cap the vacuum line that runs to it and you've created a BAP sensor! Here's the BAP sensor. It's mounted on the firewall or fenderpanel............................
Good compression #'s should be in the 150 range. You want #'s within 10% of each other across all 4 cylinders. Even down around 130 would be OK, however it may have a blown head gasket which would give you #'s that are way off too. You won't really know until you get it home, tear it down and inspect.
It's a Volvo I/C and no, you won't lose boost. The purpose of an I/C is to cool the air from the turbo before it enters the throttle body. Cooler air = denser air = more power!
I used the pic of the IHI turbo 'cause you can see better. Remove the 2 nuts at the exhaust pipe flange (arrow). Pick up a can of PB Blaster (it's like Liquid Wrench only better) and spray the heck out of those nuts. They're gonna be rusted on. Hit 'em with a 1/2" breaker bar and long extension.
The 'yard will probably just cut the exhaust pipe to get the motor out of the Capri.
When pulling the T3, get the turbo brace and oil drain tube also...................
Bring all the metric tools you can, PB Blaster, good flashlight, coveralls, rags, breaker bars, pry bars, hammer, etc. Save all the nuts and bolts too. Grab the fan if you can. You can make that work on your Mustang. Don't worry about 'red flags'. The intake/exhaust manifolds and SC throttle body are worth the price of admission! 2.3 bottom ends are pretty much bulletproof. You've found a deal, jump on it!!