I just got a nitrous express kit...
If you haven't replaced the fuel filter I would do so. You can get a way with the stock pump at that level but replacing it is cheap insurance. On a wet kit there is no need to replace the fuel injecters.
A fuel pressure safety swich is about $40. Some of them work decent other ones I have had did not hold there setting very well. If you try to adjust it right around 35 PSI it might shut off the nitrous right when the soleniods open(because of the responce time of the fpr). I got tired of mine and back it off to shut off at about 25-30psi. Are cars run about 40-43psi.
A window swich is nice but not as important with an auto as compared to a 6 speed. (I may have saved my motor with my window switch this year. The rearend came apart off the line spraying 200+ on a 3600 converter.)
The mallory 685 is a nice ignition box. Multi spark at lower rpm's, built in window switch, pulls timing, has a spark based rev limiter instead of fuel based. The factory ecm shoots off fuel to prevent over revving which could be bad while spraying.

