If I remember correctly you said you got your kit from Harris... did you get the interface as well? The interface will pull the timing when the nitrous is on and stuff. If not, I would imagine you are going to need to pull some timing for the hit so a tune may be in order. I'm not really sure how they tune for that as you need some way to for the engine to know if your spraying or not or else your tune would be off either when spraying or not spraying.
(Disclaimer) I am a novice and know only enough to be dangerous. Maybe post this question in Ed's tuning sticky.
