change the values other than the speed indicator, to show km and not miles?

You could replace the speedometer with a European one. When you purchase one new, the mileage is set initialized to whatever you order. Used ones are at whatever the donor car had.

There are all sorts of potential incompatibilities, but my guess is that there is a 95% chance of it all working. Note that there are minor differences between countries, so be sure to use a unit designed for your actual destination. I know the Irish and British units are different.

The local laws may also come into play. Since all you would be doing is converting your car to the local standard, it seems reasonable to me that it would be OK. You'll need to find a mechanic to do the work, and maybe a clerk at the car registration place to accept it.

 

Isn't it based on the Language set up, but I guess like the above poster stated there is a difference between English UK and Irish cars as the UK uses miles and UK mpg's but Ireland use litres/km.

Maybe someone more knowledgeable could confirm but maybe this is a setting or something that a dealer has to change? Perhaps they have to set the car to think it's in Ireland, Australia or Canada so that you get the display in English but the car displays metric units.

 

The Canadian car displays metric but the speedometer can be changed to MPH. The odometer, trip odometer stays in kilometers and the fuel ecomony stays in litres per 100 kilometers.

 

Then Mike would have been better buying a Canadian Prius as it would be ideal for shipping to Germany.

Wonder if it's too late for him to change now?