Hmmm...
The speed sensor on a R32 takes the analog signal from the gearbox then sends that to the HICAS, ECU & Power Steer units.
the 4WD sensors are wheel mounted from memory.
Anyway, if you swapped instrument cluster, the new cluster may be working, but may have a faulty, damaged or missing speed sensor unit inside it! search for my name and speed sensor, there is a post on how to swap the sensors over, if you have the old one still I imagine you should be able to swap sensors and fix the problem in under an hour!!!
If the heavy steering and hicas problem has come about since the speedo swap this would make sense, and also stop the data going to the ECU for your powerfc, but if the problem had been there for a long time i imagine it is your loom that is damaged.
Good luck!!!