I was thinking more from a wet standpoint, however even with a dry system it'd be cheaper to get an fpr safety switch (which would cut nitrous if the fuel drops) and not have to deal with an afc. but either way IMO the reason why most people get nitrous is because they can't afford a turbo. if that's they case, then if you're going to spend money for injectors + afc you should be putting together a turbo parts list instead of the world's most reliable nitrous system.

also about timing, that depends on your car. some cars won't let you retard your timing through conventional means - the ecu detects it and corrects. so then you're looking at an MSD BTM (which isn't too cheap) or similiar product