Allow me to cut this Gordian knot. Toyota is a Japanese company, and that means a Toyota, wherever it's built, is a Japanese car. There is is.
I've been involved in a number of discussions about this topic on Usenet, and it's amazing how argumentative and eager to split hairs this subject makes people. Although I have to say, this "profits go to shareholders all over the world" thing sets a new record for pendanticism in my exprience.
Geoff