As far as we on this forum can work out, the 3door will be officially unveiled over the next month or so, going into production approximately over summer - you won't start seeing many until autumn. Black edition or some equivalent will be even longer.
5 door isn't expected to be unveiled for 12 months after that, again autumn ish before you start to see many around.
There will be a hit to re-sale ability in the next 2 years as people who were going to get nearly-new decide "I may as well spend an extra £xk and get a new one" - but other than that it shouldn't make insane amounts of diference as Audi are only pumping out the same number of cars, waiting lists are still long and demand is relatively high.
Unless you're intending to sell inside 12 months, or are willing to change to a 3 door without Black Edition (or whatever similar thing), for more money, don't worry about it. I wouldn't (and didn't - my car is on it's way right now) worry about it.