If I remember correctly, changing the country code to ROW (Rest of World), swaps the small kph readout for outside temperature all of the time, and adds a large mph 'screen' which can be found in amongst the economy figures etc.
I'm pretty sure (but I'd have to check to confirm) that it adds a tickbox to the setup menu to toggle the large speed readout on and off too.
I swapped mine a while ago, and in all honesty, didn't find it that useful, but that's not to say others wont though
