Which one is the Catalytic Converter?

[BigLexusMN]

I know the US 200 series has two catalytic converters.

Under the vehicle, see four different things that could be the cats?

I circled both on the passenger side exhaust. One on the left is the rear of the vehicle and the other one is the front of the vehicle.

 

[TeCKis300]

Both circled are cats. One closest to the engine (right) is the pre-cat, and sequential to that (left) is the post-cat. Most modern cars are setup this way to meet tight emissions requirements.

The 200-series V8 operates as two banks of 4-cylinders. With each bank having its own set of pre and post cats.

So 4 cats in total.

 

[BigLexusMN]

Whoa, interesting. Thank you @TeCKis300