Perry01, the new tubing was replaced with 2.5 inches, as is the Dynomax Ultra Flo X 2.5 as well. For reference, stock tubing is 2.36 inches in diameter on my 5 valve V8. I'm assuming it is the same on your 4 Valve V8 FSI?
Unless I'm getting careless on my mobile device here, where is your stock H-Pipe located? I do not see it in your pics. However that resonator in your pic comes as a surprise to me! I never knew that the newer 4 valve 07+ V8 FSI engines had an extra resonator!!! I was always under the impression the extra resonator was an early 04 thing, and then VW took it out either for a sportier sound or cost saving. Again, seeing that on your FSI V8 comes as a surprise to me.
Where is the H-pipe located on your application?
I took out my H-Pipe and had the Dynomax Ultra Flo X installed as a replacement to that H-Pipe, albeit it was installed further upstream towards (but not quite at) the center of the vehicle as opposed to the H-pipe which used to be closer to the rear.
Now concerning your observation and question on my two resonators that you see right after the Dynomax, those were relocated from the secondary cat by-pass pipe location. Going back in time, I originally took out my secondary cats, which are approximately in the same location as yours, and had by-pass popes installed. I wasn't happy with the sound, so I ended up installing two puppies you see in the pic instead. But for some reason, the sport exhaust shop elected to relocate those resonated by-pass pipes to the location that you see, which is right behind the Dynomax Ultra Flo X unit.
Whatever it is that they did, holy smokes, what a smooth running V8 sound it is now! You do not hear the two firing 4 cylinder banks anymore, but instead here ONE consistent tight sound. If anything, one might call the sound "too tight!" I call it refined

. It has a very quality, high tech ring to it when accelerating, and no "*******" or cheap "POS" sound to it. It really befits the vehicle now.