Well, I just purchased the ZEX Wet Kit (#82023) 75, 100, and 125 shot jets. I got the kit, the purge, the bottle warmer, and the pressure guage for $760 SHIPPED !! I am no expert by no means, but I have did about as much reasearch as you can do on the internet on this subject (nitrous), and this seemed to be the best way for me to go IMO. I did fail to get another guage that I wanted, but I will be getting it from Autometer shortly, and that is a fuel pressure guage. I think that this is as important a device as you can have running the "oh my God" juice. Keep your eye on this guage while spraying, and make your adjustments accordingly. I may even get an air/fuel guage also, to keep tabs on that situation too, because if I'm not getting in the area that I feel I should be in, there are things I can do on my own to fix this, without necessarily getting an expensive dyno tune to rectify the problem. (Not to take anything away from a good dyno tune, because that is the best route to go)......but there are alot of things we can do on our own as far as our Stangs go, that do not ALWAYS require one.
As far as SAFE goes, I think that all in all, a dry kit is safer than the wet, because the fuel from the wet kit is what will PUDDLE on you and cause an intake backfire. But, IMO, when used properly, and managed well, today's nitrous kits, wet or dry, are the safest they've ever been. Just use it responsibly, maintain your priorities (guages, air/fuel), and just have fun !!