For a stock computer, Wet. The dry systems I've seen requires the fuel to come from the injectors. This is accomplished by bumping the fuel pressure massively. That's a problem, because bumping the fuel pressure reduces the volumetric flow of your fuel pump. Whereas, on a wet kit, the fuel is injected with the nitrous. It's jetted according to the amount of nitrous you're spraying, and in this way, it's pretty easy to make universal changes. I'll leave it to someone more knowledgeable to discuss which one does a better job with fuel distribution.
