Hi JockoT, I don't think "Pipe A" is a catalytic converter. It's just a pipe. The catalytic converter on the VS is bolted to the exhaust manifold vertically, and downstream of it is Pipe A. As you can see, Pipe B includes the resonator which is not a separate part, but welded in. I currently have a catalytic converter where the resonator should be in Pipe B. In non-VX/CX models, the catalytic is approximately between Pipe A and Pipe B. On the VX, there is no catalytic below the car, but in the engine bay bolted to the exhaust manifold.
I believe your statement that a cat normally has plugs for sensors is true. He didn't use them, as this would never work with my mechanic's configuration. Another poster in another forum where I cross-posted commented that the cat so far in the back will be useless as the exhaust is too cold, and also 2 cats in serial will cause too much back pressure among other things.
All that knowledge is the result of my research over the past 2 days, and it is more than I ever wanted to know about my car
Please let me know if my summary is wrong.