For the USDM vehicles that are in game, I noticed that quite a few don't have metric gauges. In Canada, our vehicles are similar to the ones in the USA except for a few minor differences like DRLs and metric gauges. I'm suggesting you should add metric gauges to 1977+ model year (when metric signage was implemented) USDM vehicles when you remaster them (to those that need remastering) and add the gauges to those that don't need a remaster.
I say just get eu specs and put canadian plates on them like this. Or just change the plate design for a canadian plate. Otherwise idk what do tell you.... Canadian plates pack- https://www.beamng.com/resources/canadian-license-plate-pack.912/
while yes, there's a few finer details like amber/clear taillight lenses for the turn signals, reflectors, and maybe a few more parts I missed, I mean more of the cars that wouldn't be sold in the EU, but would be sold in Canada like the D-series, Grand Marshall, Bastion, etc.