My buddy is looking to get a 1999 Mercedes-Benz C230. There is a problem with the instrument cluster. The odometer has one of the lines burned out, and in order to pass inspection we would need to replace the cluster ($1,200). He doesn't want to get a new one, so I told him that you could put a used one in. I know a lot more about domestic cars than imports. On Chryslers, the mileage is stored in the PCM, making swapping gauges simple. Fords, however, store in the cluster, making it more difficult. My questions are as follows:

1) Where is the mileage stored in the car?
2) If it's in the cluster, and i have to swap out the internals, how easy is that in these cars? (It was fairly easy in my Mustang).
3) Is there another way to fix the gauge cluster? I'm thinking a solder simply came loose.

any input you guys can offer would be helpful. keep in mind i know almost nothing about imports.