You can bribe officials in Vietnam/Mexico. So they'll be your country of "final assembly".
I doubt the Americans will let them do that so easily.
They already are. Just one tiny well-explained example, although it's utterly rampant:
https://www.npr.org/2024/08/23/1197961495/the-trade-fraud-de...
No bribery required though, at least in most cases.
They tried stockpiling aluminum in Mexico during the Trump ban and that was shutdown quickly. I guess they just have to be more convoluted about it. I wonder if Trump will do something like “tariff China and any country that doesn’t tariff China itself (transitive)”, but it feels like it might be futile to do that.
So they will have to bribe officials in Vietnam or Mexico and bribe officials in the US.
A quick google search of "BYD Mexico" tells me it is already starting.
BYD can build cars in Mexico, they already build buses in SoCal, that’s not an issue. The question is if tariffs are going to apply just to final assembly and will they be easy to avoid by assembling elsewhere.