But Tesla is not brake by wire like that. The brake pedal is connected directly to the hydraulic system, right?

Whether or not something has tariffs depends on the type of good and where it is from. Overall it’s a complicated system. But we’ve had free trade in North America for a while now which is why there haven’t been tariffs between Canada and the US.

I don’t think you are allowed to sell patent infringing products, even if you didn’t make them. The manufacturers may not be in the US so going after them could be more complex. I believe patents restrict rights to make, use, or sell.