I have a b16 SIR2 that came with a y21 LSD transmission, but the case leaked and I replaced it with a more common s80 about 2 years ago when I rebuilt it.
I added carbon lined synchros, new bearings, new rubber, new gaskets, measured and replaced as need, full rebuild.
I was driving on the freeway about a year ago and a piece of plate steel was pulled up by the wind, and busted a hole in my s80 transmission case.
This is an article about how I got a replacement housing from the junk yard.
This is what it looked like when I found a 1995 Acura Integra with a Manual transmission.
I started with removing the suspension and pulling the axles out of the transmission.
I removed all the upper things in my way (starter, wire harness, brackets, hoses, etc.).
I then went under the car and removed all the bolts needed including the half shaft.
After I was sure I removed everything, I went to the top and removed all but the top 2 bolts on the transmission to the engine, and the top transmission mount.
In the video, I have the transmission held on with the 2 top bolts, and everything removed and unbolted.
I unbolt the last bolt on the mount and let the engine tip over for easy transmission removal.
After I let the engine and transmission tilt over, I put tires under to lightly remove the transmission with no risk of dropping it on the ground.
I held up the transmission while my girlfriend removed the tires, one at a time.
Now the trans is removed. SUPER GREASY!
I remove the casing I needed and put the top bolt back on.