One thing to consider.
Stick with me for a moment to make a point. In the 97'* myself and Matt (Canadian) both happen to have, we were investigating a way of making the HUD reading able to swap from KMPH to MPH and back. Older years had a switch, ours don't. Through the research I found that in the US models a certain pin that is ground or not to control this feature is wired from the hud to the main dash connector. After that connector the US models don't have any wire continuting to the ground splice by the passenger door, the Canadian models have that wiring.
My point is instead of using a universal item with a switch like they did previously, they simply had a different main vehicle harness for Canadian vs US. I'm sure there were other changes as well, but when you look for the wiring....don't stop if you find some in the column, follow it all the way to the radio.
00 Regal GS: All kinds of cool stuff.