Hi JK. I'm currently in a similar situation. I have a Japanese Import GT86 that has its original KPH speedometer. Before I take it to the IVA I want to have a MPH clock installed that will show the trip metre in miles and not Kilometres. I've bought a UK clock and had swapped the clocks over from the jdm kph clock and when I come to turn the key it won't start. Have you swapped your JDM clock to the US mph clock and does it work?