Sorry Guys.
I'm trying to work out where both ends of this should go.
I have no boost, no power and I think I should connect into the vacuum circuit. but does one of the connections get blocked off when I do?
Pictures appreciated.

sorted...
one of these goes to the turbo solenoid (via the BMW Vaccum pressure vessel - but not required)
the other goes to the EGR solenoid - mine is now blanked off, but runs perfectly.