I would definitely talk to people using it in their spec v's. Get on a nissan forum and ask, ask and then ask some more

There are definitely cheap ways to running nitrous, but is it worth the risk?
If you end up doing it the right way I think your going to find out it's going to cost you. I had a 225 Quattro TT, I was thinking of doing around a 50-75 shot. I put together a list of parts I would need and it was close to 2k minus the installation if you were to have someone do it and the tuning involved to make sure you're running safely.
I just thought it wouldn't be worth the risk, because if I blew my engine because something didn't go right, I would have a whole mess of problems and more bills.
If its really something you want to do and have your mind set on it, call a good tuner and I'm sure they can recommend a kit and put a good tune together for you. It would probably be beneficial in the end knowing that you had it professionally done, put you at ease.