Frankenstein B16/B18C swap into '91 CRX Si

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Hello all. I'm finally going to do the swap that I've always wanted to do. Life has been getting in the way for the last five years but now that I've started buying parts and got the motor I'm pretty close to starting. I have a few questions that I haven't been able to find answers for though. Also, I forgot to mention in the title that this is a '91 CRX Si.

The motor is a B16A (Don't know what year) block, with a 97 OBDII GSR head and a GSR transmission.

I have the B series mounts from innovative along with the shift linkage in the mail right now. I also have a P72-A04 ECU.

Here are my questions:
Since the transmission is from 97, will I still be able to use 89-93 DA axles?

Do I need a different ECU? Or will it be possible to get a harness that'll work with this setup?

What kind of mounting problems am I going to run into when I'm trying to put this thing into my engine bay? Am I going to have to tear out the AC? I already know I'm probably going to have to pound on the frame.

Also, what about the airbox? Is it going to be at all possible to use the stock airbox or will I need to get something for that too?

Lastly, the motor has headers on it that go from 4 to 2. I'll take a picture later and upload it, but does anyone know what kind of exhaust system I can run with this? I don't know if I know of an exhaust shop that'll be able to make something that'll go up to it...

Thanks guys!

P.S. I posted here about two years ago when I had a 94 GSR motor - unfortunately life happened it and I had to sell it. Really kicking myself in the ass over that because I got all of the stuff from the previous thread for $500.

I still however have the P72 ECU, which will actually work with this one correct? Or should I pitch the OBDII distributor off of the head and get an OBDI distributor and ECU?
I can't answer your question on the axles. You should be able to use that ECU, but you will need to buy an obd0-obd2 jumper harness. You will also need to run a few wires for the GSR IAB's, and maybe the knock sensor, IAT, and 4 wire o2 sensor. Check on that. I don't believe that the stock airbox will work becuase the GSR throttle body sits lower in the engine bay compared to the D16A and B16. You might be able to buy the inlet tube from a GSR and mate it to the air filter box. As for the exhaust, it sounds like you are missing the bottom part of the exhaust manifold. Many 4-2-1 headers (including the stock one) are a 2 piece design.