Is your system at the min stock?
If it's the same set up as the saloon 1.8T (190bhp) system then it actually splits just before going into that box you cant actually see it by just looking under the car but I had my friends motor up on the lift few weeks back and he was considering doing what I've done to my 3.0 V6 and removing that box, his system looks very similar to mine only difference was mine is 2 pipes from the front to back and his (like yours I suspect) was one pipe right up to this box and 4-5 inches before it splits into 2 then its 2 out the other side of the box too,
So no Y section is needed you could just do as I did and cut it out and replace it with straight pipe (weld in) dead easy took me around 30 mins to do.
The section I cut out: