Here's my situation...I have an '03 Civic EX (D17A2) with really just I/H/E and Denso Iridium plugs is all I've done. I read everywhere that other bolt ons will give me "some" power, but not much.

I really don't race but want some extra "umph" there when I want it. I know turbo is more consistent than nitrous, but I'm not really sure if I need consistency as I really just want the power for "shits and giggles". I'm looking particularly at a Zex kit as I'm a noob to nitrous and dont wanna blow my engine. Another thing is I've dropped some cash on an intake and header that from what I understand i'd just have to bag if I go with turbo. I'm also concerned with engine life. I'm sure I'd "get on it" alot more if I had the turbo, where as nitrous I can turn off and limit myself. (smack myself in the hand when I go to turn it on)

-How much more total power will I get from turbo vs. nitrous.
-Dollar for dollar, as turbo is about 3 times as much as nitrous, what do you think I'd be happier with?
If I go with nitrous, is Zex a good kit? How big of a shot is good for a noob?

Thanks, I'll appreciate any tips you can give me.

 

Keep the n20 at about a 55 shot and you'll be fine.
As far as the turbo goes, you will gain more power, and if tuned right it will respond just like a factory car (civic, just with more power)...
I have never used n20 so I cant speak for it's reliability, and ease of use, etc. I have been boosted though for about 5 years, I will never go back to trying to make power N/A all the money I wasted could have been put towards making my car actually faster. Thats me though.
If your looking for constant reliable power that you don't have to worry about (or refill) then a turbo is the way to go hands down.
If your looking for a little bump in power, just for shits and giggles then go with the zex kit, get it tuned and leave it. Have your fun when you want it.
Or maybe consider a s/c, you'll make as much if not a little more power then the 55shot, and it's safe if tuned and LEFT ALONE. You can still use your header, and possibly your new intake. With the turbo you'll make more power then both, be just as if not more reliable, but you won't be able to use your intake or header.

But if your like 95% of the other people looking for more power, you'll eventually end up with a turbo if you start with the other two methods I listed. I don't believe I've ever seen anybody sell their turbo kit infavor of running n20, but I've seen lots of people sell their n20 set-ups and go with a turbo. Some even use both..

Think about it figure out what you REALLY want, and research that.
I told myself if I could hit 150whp I would have been happy (had a d15b7), then it became 200whp, then the engine swap happend and the goal was 250whp and that was it........currently I'm sitting at about 285whp (about 320hp at the crank)...and planning out how I'm going to run 11's with 300whp (new tune in the works) the next time I hit the track....it's like crack, one you try it your addicted....
It starts out where you race some other civic's and beat them, so you move onto integra's and other cars in that range, the next thing you know your racing corvetts's and audi s4's on the highway....(Well for me it's on the track now)...then you figure if I can take these cars why stop there? Well I havent, I've now moved on from the vette's and mildly built muscle cars onto the blown muscle cars....basically anything that doesn't run a chute yet(or slicks as wide as my car)....I'm staging next to them trying to have a fun night of racing.......I win some and lose some, it's all in the name of fun...