Haha! Yay! More misconceptions about N20.
*disclaimer* I don't like nitrous. I think it's ricetastic and a way to shortcut good powertrain design. That being said...
The zex kit is a very simple system that works remarkably well. It simply increases fuel pressure based on bottle pressure. The regulator of theirs clamps down on the return line to the tank to accomplish this. It has a conventional N20 jet placed wherever you want it. There is no "pin hole" to clog or any "leaking pressure" to speak of. Contamination in the system is always installer error and will simply clog the nitrous jet. This is why filters really aren't needed. Alot of the more popular kits (like the ones you can get at pep-boys/vato zone) include filters because Ray-Ray installing a system with nothing but his favorite set of vice grips just might introduce some contamination. Even if you do get contamination, your motor will run momentarily rich... stumble and die. The nitrous user will simply have to take his sideways hat off and re-start the car.
The problem with systems like this is that nitrous distribution will always be slightly un-even between cylinders. With lower power kits this isn't a problem because they run slightly rich on all cylinders to be safe. An 80 shot is really pushing the limits of what you can get away with. You will probably end up burning the #4 cylinder over time. The problem with uneven fuel/nitrous distribution gets more pronounced on turbo cars... and if you're using a RRFPR for the turbo kit... forget about it.
I REALLY don't like the idea of wet systems on DIS ignition cars. If you are still on the nitrous and have to snap the throttle shut for some reason you can cause a pretty bad explosion in the manifold. The waste cylinder fires at the top of the exhaust stroke. There is just enough valve overlap there to allow the intake valve to be open when this happens. If you have a nice dense fuel/nitrous mixture hanging out in the manifold... intake valve open... plug fires... *boom*. Have I personally seen this happen? No... but it's a very real possibility and does happen from time to time. Wet systems will cause carbon buildup in the intake runners over time and I have also seen MAP sensors fouled over time from running wet systems. That can be obnoxious to diagnose because they will sometimes give accurate readings on a bench.
Let us know how you do at the track. Rember to keep the rev's high before hitting the button