I need to rebuild? (90%shure)
 

Well I have had my fd for about a year, and have been slowly bringing her back to life and learning about the car at the same time. I now loose coolant everytime that I park the car (overflow). Here are the specifics of what I have tested:
-Thermostat housing, AST caps have been replaced.
-Pressure test to the cooling system seems ok. If I take it up to 15 psi i might loose .5-1.0 psi over a period of 8 hours. ( I don't have the right adapter for the thermostat housing so I tested it at the aftermarket AST.)
-No trouble starting the car, never runs rough, no smoke at startup, though I still have the main cat (if that would affect things).
-Champagne bubble test I get lots of tiny bubbles (like carbonation) at idle(87 C). If I tug the throttle cable a bit, I get a couple of large bubbles to come out every time.

Like I said, I am 90% sure that I need to rebuild. I was just wondering if there was anything that I might be overlooking?

all help/comments appreciated.

Sounds like you got an O-ring seal leaking.