Well, I feel for both sides. The problem is that most people who pirate a game do so because they've been disappointed a lot by companys with a lack of support and quality (see gothic 3 e.g.). I fully understand how people then say "Well, I won't pay 50 bucks to get a game that turns out to be complete bullsh**". Personally I think it is morally acceptable if someone pirates a game to try it out and decide whether or not to buy it. You're allowed to try out a car as well, lie down on a new mattress that interests you or taste a good wine you might wish to buy. And you won't try out the cheap version of the car, or just a piece of the mattress or a bad year of the wine either. You get to try the real product. That is rarely available so far in the gaming industry.
However there are awesome companies like IC/Stardock who feel unjustly punished by that behaviour, which I understand as well. The only advice I can give is not to take it personal. You guys are doing an exceptionally fine job and the very fact that so many "pirates" speak out here and confess that they originally pirated the game and then bought it afterwards should be a strong indicator just how enthralling the gaming experience is that you created. The idea to update only via impulse is actually a good way to persuade "pirates" to buy the original, because the support and improvement that IC/Stardock is offering is in itself worth the money for the game. So please keep it up and do not feel discouraged by the confessions here (except for omnidex', that is, but I feel he's quite the exception) and on the contrary feel proud that the very quality of the game persuades people who already (illegaly) play it want to support you by purchasing it!