Ive just installed the Zex kit for my 06 GT. It was very easy and I made it VERY Stealthy! Ill post pics this weekend while i am rewiring all the switches to a central location..
I wouldnt go on Modular Fords and ask about Zex Nitrous systems. The Mods there are notorious about deleting threads that arent about supporting vendors.
I feel that the Zex nitrous system is the most user friendly kit available for our mustangs. Ease of instalation coupled with track proven results are what set this kit apart from other makes such as NX and NOS.
I've used a zex kit on a SVT Focus and a NX kit on my Bullit. The Zex is easier to install because the engine mounting parts are all in one box vs. seperate. I've been told by Brad's Custom Auto(featured in many Mustang Magazines) that the NX bottles are better than Zex for feed. I think that either kit would make you happy as long as you don't mind filling the bottle. Make sure you get a remote opener and purge valve. A blanket warmer isn't as important unless you are truely tracking it. For occasional street use, there isn't much use for a warmer as it needs to be on 10-15 minutes before it helps, however having the ability to open the bottle from your driver's seat and purge excess nitrous from the lines after a run much more convienent.