the pipe off the manifgold you have teed into goes to the charcoal canister under the front drivers wing, via a solenoid. this also draws fumes from the petrol tank as it is part of the emissions recirculating system.

you need to plumb the boost guage fitting as close to the manifold as possible, but NOT teed off on the map sensor OR the fuel pressure regulator.

look at mine:



from the left:

Fuel pressure reg pipe and the blanked off one is an auxillary feed for Stu to use when mapping.

top is my SPA ACT sesor

Middle is the ACT sensor for the ecu

Big canister at the bottom is the SPA boost pressure sensor

the 90 degree silver elbow on the right is for the map sensor feed