On my 2023 Model Y, the turn signals are amber and I did not have to replace or modify them for the inspection. For another model or year, I would check the actual car.
Charging works too. Mine is blocked from Tesla Supercharging, but I charge at other networks. I have already done a roughly 950 km trip with stops at FINES and Electrip. That is my experience with this car, not a promise for every blocked Tesla.
I also recently came across a Facebook post where an owner said they charge their US Tesla through an adapter without having replaced the port.
There is a community report of LTE working on HW4 without a modem swap. Working mobile internet does not automatically mean Premium Connectivity is available; that needs a separate check in the app. There is also a post about European maps downloading automatically after an update. That is a report about maps, not confirmation that the whole car converted itself.
So I would first check what already works on the actual car. If charging, internet and navigation are fine, and the missing radio frequencies do not bother you, you may not need to modify anything just because the car came from America.
