Remember the ~$250 including a new lcd and some other little things.
The kms are kept within the eprom, within the cluster, it is not part of the
ECU or the
BEM of the car.
You may be able to just change over your eprom from your existing dash to your new dash, but i'm not too sure how to do that. Voodoo, just put in a brand new one, and re-programmed it. My guess would be about $100 for that.