UNC Decision day in 8 days

I wouldn't bother. A couple of reasons -

1) You'll only talk to a low level receptionist type person and wouldn't have any impact anyway.
2) In all honesty they've probably read your application several times and have already made a decision. If not, a quick phone call to ask a few questions will hardly make or break your app. Moreover, you and everyone else would probably be calling this week to ask these kinds of questions - it doesn't differentiate you in any tangible way.
3) Even if you do talk to an adcom, what would you say that would be a meaningful addition to your file?

I know its nerve racking. Trust me, I know. I can't believe how on edge I was for Cornell, a school that I wasn't even really all that interested in (though I've warmed up to the idea a lot). Find solace in this fact:

The poor bast*rds like myself who applied to Kellogg get to sit on pins and needlees from now until Jan 8. We could get a call anytime between now and then. I used to think this was a "good thing" and liked that Kellogg rolled admissions during these last few weeks - and I used to curse the GSB for not doing the same - I've since come to realize I'd much much rather have to wait for a single date and bite my nails like mad for 8 or 9 hours than wonder each and every single day for the next 30 days. For instance, when it was reported that Kellogg might be releasing decisions last Friday, what pops up on my cell phone? An 847 area code number. I answer it, "Hello is this X?" I mean really, could you get my hopes upanymore? It was just a store following up on a call I'd made a few weeks back. Moments like that are going to drive me absolutely BONKO for the next 30 days.

So, sit back, do the impossible and try and relax....