Although my IIci is already clean 32-bit, I still put a DougG3 ROM in it with a copy of the IIci ROM on it.  You just jumper it and it uses the SIMM instead of the onboard ROM.  You can do the same with the IIcx if you have a clean 32-bit ROM.  Just put the SIMM in and apply the jumper, you're ready to go.

Edit:  Well, DougG3 also loaded in-ROM the DayStar 040 drivers on my SIMM.  Turns out my DayStar didn't like using the SIMM versus the onboard ROM, but he fixed it for me.