what motor is in your car?
I ask because there is one very very very important wiring / etc. difference between a CRX and a 94 GSR.
In a CRX, there is a cable that goes from the transmission to the back of the cluster. The speedo cable spins along with the transmission when the car is moving. The VSS (Vehicle speed sensor) assembly is located inside the cluster. You will need this to keep your ECU happy.
On the 94 GSR, the VSS module is mounted to the transmission directly. An electrical signal from the VSS module is sent to the cluster to make the speedo move, and to keep the ECU happy.
If you want to install a 94 GSR cluster in your CRX, you will need and electronic VSS to mount to the transmission, to rewire your car to feed power and ground to the VSS at the transmission, to run a wire from the VSS to the cluster in place of the speedo cable and finally to run a wire from the VSS to the ECU so it doesn't freak.
The instructions for a SiR cluster into CRX are going to be fairly similar because the JDM CRXes came with electronic speedos just like the OBD1 cars.
Hope that helps.