Red2000GT is on the right track. It's neither an H or X pipe. If you look at the ProChamber Diagrams, the front 2 parts of the exhaust piping simply enter a square chamber, then the back to pieces exit the chamber and connect to the cat back system.
| | | |
| | | |
\ \ / /
then;
______
| |
|empty|
| |
----------
finally;
/ / \ \
| | | |
| | | |
crude, I know but, just imagine it like this but assembled.