You'll probably be stuck with a instrument cluster that has the KPH numbers in large font. The biggest issue is the warranty which you've already found a fix for anyway.

Do you live in a county in Ohio with emission testing? If yes, if they just check for codes you probably will be fine but I don't know what Ram does with the OBD reporting for Canadian sold vehicles. Some other manufacturers just send the USA engine calibration over to Canada so those would be fine at an emissions check station.