For the DSBC: The skinny hose on the back of the unit should hook up to a vacuum source, What I did is t-bone it to the same hose that runs to my Boost gauge-saves routing another hose through the firewall.
For the Actuator unit, there are two connections, the IN port is for the pressure source from the turbo, the OUT port connects to the actuator or wastegates
It is my understanding...since the directions are not very clear for our vehicle, that one of the hoses will fit onto the nipple that sits on the elbow of the Y-pipe. (probably the IN port)
Stealth316.com has a description with pictures on how to install an EVC IV, take a look to determine which hoses to connect to. Trying to describe it myself just makes it more confusing. But the hoses you are looking for branch off of an F fitting and run up to the factory solenoid. One of these is the actuator hose.
The instruction manual says to mount the control unit within 3 feet of the turbos or it may impact boosting performance. You can run the harness plug through the firewall plug above the steering column area. What I did was slice the plug using a long butcher knife, then stuck a metal dowel rod-(a straightened wire coathanger wire would work) through the hole and into the passenger compartment (from the engine side) then used duct tape to secure the plug to the dowel, then pulled hard until it came through the dash hole.
I just routed the harness this weekend and mounted the unit in the dash below the stereo unit. I plan on hooking up the hoses as soon as I figure out which is which....the old EVC IV has 3 hoses not 2.
Lord Warlock