Is your hatch Si or DX? You have a GSR tranny. What motor do you have? I would/ve just used the cable since your car is cable.
Now for the cluster you can use it in your 91 however, you'll need a I believe it's a elecric speed sensor they call it on 92 up Civics.There's a write up on cluster swap in a 88-91 EF's.
Good Luck
Post pics when done.