Ok... So here is the update...
The Good:
- The new AVO intercooler is AWESOME! I've gained about 2psi under boost. If "feels" (hate saying that) like it spools faster.
- Install was pretty straight forward, despite the instructions being a little vague at times.

The Bad:
- I still have a vacuum/boost leak... GRRRRRR!!!!!

Testing:
- After doing a little looking I was able to find a helpful post regarding vacuum leak testing. I do have a COBB AccessPORT, and was able to pull the "A/F LEARNING 1 A" reading. I guess if you have a vacuum leak at idle it will max out at 15% (max allowed adjustment value). Mine was reading that... Now its just a matter of tracking it down. I have checked all the normal and easily accessible vacuum lines (including the blue one under the intercooler) and they appear to be connected and in good order.

So, I have more boost, but it is still unstable. The original intercooler had been repaired before (previous owner, and I didn't know that it had been... used the JB Weld as well). I'm going to take the car to Oakos Subaru (tuner shop and parts dealer) and have them run a pressure test on the intake. I "think" my intercooler to throttle body hose might be the issue. I couldn't even get to the front hose clamp (it was tight). It may also be a cracked/aged line. The leak test will show where the problem is.