GnarlyCar

So I picked up a 98 ZJ about a month ago, which apparently born and spent most of its life in Calgary, AL, Canada. I'm in Minnesota, and kilometers don't compute here. It's bad enough I have to do snooze button math when I wake up, but now I have to do calculus in my head while I'm driving to work to figure out how fast I'm going.
Originally, I thought I could just pick up some gauge overlays with US units of measurement and just stick them over the old ones, but apparently the needle on a regular US speedo sits in a different location at 60mph than it does at 60mph on a Canadian speedo, so that plan went right out the window. It looks like I'm gonna have to swap the entire gauge cluster if I want to make this happen. They come cheap enough on eBay, and I like to think I can hold my own with the contents of my tool chest, but I'm wondering if the needle position is actually determined in the gauge cluster or in the computer.
Ideally, there's someone here that's done this before and can tell me what it'll take to make it work, but if not, I guess I'll continue doing intellectual calisthenics every morning.
I only have a given amount of smart to use on any given day, and I don't want to use it all up before I even get to work, so any help you folks can provide would be greatly appreciated.

DJeXeCute

Grab a new cluster and throw it in thats all there is to it.