This is my attempt at a thorough diagram of all the little vacuum hoses attached to the intake of the EJ22T on a BC/BF-chassis Subaru Legacy Turbo.
I've included Subaru part numbers as well as hose sizes because many of the stock hoses are vulcanized into appropriate shapes.
It should be possible to replace nearly all of these hoses with generic vacuum line sold in bulk, but there is an advantage to using the stock hoses: the stock hoses' shapes make their routing fairly intuitive so mistakes are easier to avoid.
Aftermarket silicone hose can last much longer than stock rubber hoses, though, while also costing significantly less.
Click on the thumbnail for a large bitmap view.
I also have the scalable vector version in PDF: ej22t_vacuum.pdf
The PCV hoses are omitted because they would make the diagram very hard to read. This composite I made from the parts sheets actually does a decent job of diagramming the PCV system:
Please let me know if you have a correction or comment.