Quick note: I'm not speculating on when exactly Bitfinex finally goes public with DRK exchange, however with the way these things work out, I would expect a sharp spike up followed by an almost immediate sharp drop ("buy the rumor, sell the news") initially and probably a dull decline lower over the following days along with ridiculous FUD here as many traders initiate shorts.
Eventually after a couple days I'd expect stabilization though and eventual long-term price increasing as the longer-term traders realize the valuable utility that DRK brings. Of course, this is assuming the MN's payments work without forks.
JL