"For Waitlisted friends" :
I got admit after being waitlisted twice(Applied in ER and got admit with R2).
I guess, it's important to convey that UNC is still on your priority list. In addition, showing your understanding of program and showing that you have enough understanding of UNS to hit the ground running, works in your favour. Obviously, any promotion or GMAT improvement is great., I had promotions, but no GMAT hike. Good Luck and don't loose the hope.
May I know the reason, why you have waitlisted twice ?? Did they give any feedback on your application while you waitlisted. ??
I'm waitlisted now. So please reply me...!!