Which Nitrous System.

i've used both the zex kit and the compucar kit. both worked good, but with the zex kit they had to replace two bottles. both had leaks. the third bottle they sent me worked fine and i used it many many times. the compucar kit was good but not quite as simple an installation as the zex. all in all i'd choose either kit again, depending on which one i could find the cheapest.
 
I run a trickflow plate kit. Fits between the upper and lower intake kinda like a phenolic spacer. It is more expensive, I believe that mine goes for a round $650 but I am much more comfortable with it I don't like the idea of injecting fuel from a wet kit and having it run through a long plenum upper intake. To much time for the fuel to drop out of suspension. That is just my opinion though plenty of guys use the nozzle wet kits with no probs.

All of the kits the guys have brought up work great and each one will be fine but I prefer wet kits. You don't have to rely on your injectors to supply the extra fuel as it supplied via the fuel solenoid and jet and it adds the correct amount of fuel each time. And if you feel that you need to run a richer mixture due to fuel pressure or what your comfortable with then all you do is change out the fuel jet to a little large jet. Pretty simple.

Remember to figure a couple of things into the price of the nitrous kit as well. Get a window switch either a digital one or one that uses the MSD rpm pills. The first time that you miss a shift and hit the rev limiter you will see it is $100 well spent. The last time I was at the track I hit the rev limiter and was happy I had the window switch in to shut the nitrous off. If the kit doesn't come with one you will also want to get a nitrous pressure guage, even if it is one that attaches to the bottle nut. Consistent pressure is the key to consistent times. A bottle heater will help with this as will a purge kit but they can be added later on down the road.

If you are only going with a 50 or 75 shot then you should be fine with the stock plugs but will need to bump your timing back 2* for every 50 hp increase and you might want to look at gapping your plugs down to around .035-.038".

Nitrous is fun and addictive. My heavy a** boat convertible AOD is going 12.7s on a 100 shot and that is great, for now. The only time that I spray is at the track especially the way everything is down here for street racing, the last thing I need is to get caught messing around on the street.

Like I told Marlboro_Man it costs me around $23 to fill up a 10lb tank. So its not that expensive to mess around with down here.

Good luck with whichever kit you choose and you'll have fun.