I can only speak for 6th gens:
I have a 4cyl - 5speed.
All five speed trannies in 2000 came from Japan. Autos- could have come from their too.
So, even American built cars in the 4 cylinder were 25% Japan.
Notice too, those cars also use Denso parts under the hood as well, also built in Japan.

The V6 cars have nothing from Japan. Under hood parts are Delphi instead of Denso.

Being built in Japan doesn't make the car perfect. Take a run down on Lude stats sometime. All Ludes were built in Japan and percentage wide--the stats aren't perfect.