When eliminating the heater core and the fiav in the throttle body you take away a key part of the coolant system. You remove a thermostat bypass loop that helps keep the coolant pressure down and the water pump from working extra hard as it is fighting to pack more and more water into the thermostat housing. This can do several things from forcing the thermostat open prematurely or causing the pressure to slowing the water pump down putting resistance on the belt.
By putting in a by pass loop it allows the thermostat housing to be evacuated by vacuum to the water pipe preventing any issue.
to do this mod i used a nt water pipe as my turbo was not water cooled. I trimmed the water line that ran back above the tranny to about 3 inches long.
using the stock water nipple that the heater core return used.
using a dayco hose part number c87617
that part proved difficult to find but advanced auto had a matching part 303617
the part was a direct fit. It did the job perfect of completing the bypass loop for the thermostat and it has a clean stock look
thanks to gofer and 19Eclipse90 for the help on this one