Most likely dry rotted "T" fittings around the Boost Bypass Valve, Fuel Pressure Regulator at the front of the fuel rail, under the blower snout to the Lower intake, and back around to the MAP sensor. That is a big issue with our cars...another is the line from the throttle body to the EVAP canister on the back of the blower housing...and sometimes even the black hosing from the vacuum tree on the top of the blower itself. Might also be a bad throttle body gasket but I'd spray some carb cleaner around the engine bay and watch to see if any spot you hit changes the idle.
