I have a 1.6 TD Could I retrofit the TDI breather hose from AAZ or an AHU to equalize the crankcase and the head vacuum pressure? Could I just plummet into the line that goes from the PCV valve on the valve cover to the intake tubing?

#1 on the diagram
The aaz block is taller, you have to cut some. I have one on my 1.6 it is possible.
I didn't have to trim any
.:Sent by pneumatic tubes
do you need the exact part; for ccvent you can also easily use a hose, has to be compatible with oil, etc. get thick hose, not that thin vent stuff, reinforced by nylon or similar would fit on and work well, the breathing flange is the only other thing. i found 1 (breather hose) for an ahu, same, from block to the valve cover top thingiie, they can crack after so long, hose prob cheaper to replace 2x that 1 stock hose your looking at.