Which one is the 3rd-cat?

Acura Tl exhaust system parts

I have question about the 3rd-cat regarding it's location and what it do.

First of all, is that the location of 3rd-cat in a tl that everybody is talking about that will result me more power and great sound by simply getting rid of this?

Also, what is 3rd-cat's primary duty? What is it designed to do ?

Sorry about so much newbs question, I'm beginner trying to switch my exhaust system to gain more power and throaty sound..