Another thing to keep in mind. That '5 second knob hold' only switches the speedometer. When I got mine (in the US as well and brought it over to Ottawa - after a 5,000km drive from Santa Monica, subject to its own post
) I wanted everything changed to Metric (temperature indicators on the air conditioning for example). In some cars the only way to do is to hook up a computer and change a flag that sets the car to 'Canada'. I saw the dealer in California (Porsche one) do it in front of me (and by the way, at no cost
) and it worked. What else gets changed when that flag is set I have no clue but they did it for me and I was happy.
Not sure if this is something you can set with the Durametric or if you need the full blown Porsche own system to do it. Others can comment as well.
There is no need to change the speedometer 'labels' at all. Mine passed inspection just fine.
You MUST bring the car to an authorized Porsche dealer though, no matter you have all done on the car in the US. They must 'inspect' it and issue you a letter. That alone costs $500 plus taxes. Had to do it unfortunately.
CR