How big of a nitrous shot can the stock fuel system support?

[harman.khinda]

I'm at 200,000 miles on my 2010 Z. Once the engine goes I'd like to install a stock rebuilt one and add nitrous. I need something that can pass smog ecu check (visual will pass ok) which is why I'm going with NOS. I could go stillen but I think its crap quality wise and this route is cheaper. I'm thinking a 150 shot should be ok based on the 350Z forums.

I have test pipes, full exhaust, hps tubes, and k&n panel filters. I would need colder spark plugs. Would I need a different intake for NOS or would this be ok?