Ok, if the piping is stock these are the main places:
-Rubber 90 deg elbow that comes off the compressor housing of the turbo.
-Rubber elbow that goes from the metal hot pipe to the metal elbow that leads to the intercooler
-Rubber hose that joins the metal elbow to the intercooler
-The factory Recirc valve that sits on the intercooler (if the vacuum line is disconnected it will leak really badly)
-The rubber pipe that joins the intercooler to the plastic cold pipe
-The rubber adapter that joins the plastic cold pipe to the throttle body
-The rubber pipe that joins the plastic cold pipe to the IAC valve in the manifold
-The rubber pipe that goes from the recirc valve to the intake pipe just after the air flow meter
-The rubber pipe that joins the intake pipe to the the EGR system
I think thats all of them
Undo each clamp and check the hose clamp for damage. If its bent in any way replace it - they are cheap anyway. Also clean the metal and plastic pipes off with a wax and grease remover (prepsol) to stop the rubber slipping off under boost.
There are also a number of 8mm and 12mm vacuum lines. These go from the intake manifold to the carbon canister, the factory boost control, fuel pressure regulator and recirc valve. There is also one that goes from the cold pipe to the wastegate system. These should be checked for splits and damage too.