Running N2O introduces risk as any other performance modification, you are going outside of OEM specifications. Be prepared to fix your car if something breaks. With that said, I'm running 100HP shot on my 2009 7AT. I've been through about 6 tanks and everything is running like a top.
My Build:
Audio Dynamix 370z Nitrous Install
This thread has a lot of good info too:
Nitrous build is finished