Sorry for interrupting this thread, I was going to ask the same thing!!.. I fitted a defi boost gauge to my drivers side dash vent in the weekend and was unsure as to where to plumb the gauge pipe to, so I tapped it into the turbo actuator vacumn pipe as a temporary basis.
i was going to post a question as where should it be connected as I know where on petrol cars but am unsure where on a 2.0 tdi engine.
my gauge shows -6 bar on Tickover and goes up to 0 bar when you change gear when driven hard.
looks like I will have to tap into this egr pipe as well then, does anyone know if there anywhere else that you can tap into for the gauge to work correctly.