Okay, here is the deal... It's an indirect value change that will shift the HUD to metric. You need to go into settings and change the 'distance' units to kilometers. Not enough to just change the unit for speed to kph.
After that, the HUD will update.
NY, be careful as the HUD's speed limit sign if showing mph when reading Euro signs will round up/down within 5mph. This can very annoying firm me. But, if you are cool with it, then thanks!