Insturment Cluster w/ Tach

[joeyicu]

so i may be getting a new instrument cluster with a tachometer and was wonder how to go about the install and still be able to keep the mileage i have on my car.

i know with ford IC's it was made into the unit and nothing could be done about it on certain ones, then on others you could use the diagnostic software to pull the info out, then swap the IC's then put the info from the old IC into the new one, is this how the Toyota's unit works or do i have to just deal with what ever mileage is on the cluster im getting?