Corola MPH to KMH gauge

[dpedri]

Hey I need some help, I am trying to figure out how to change the gauge from mph to kmh. can I just slip in a different plastic gauge? or do i need to replace the whole cluster gauge. Also if I have to replace the whole cluster gauge will the mileage be reset or is it not stored within the gauge itslef?

2005 Corolla Sport

Any help would be greatly appreciated