John,
I did some reasearch on this nitrous system, what it dose is cut off the vacuum to the fuel pressure regulator. This diverts all the pressure to the fuel injectors instead of back to the gas tank. Thus produces a rich mixture. the problem is i don't know weather this system works with CIS..... It may just work with EFI.
Another alternative for producing a rich mixture is to have the cold start injector open when the nitrous is on. What do you think?
Adam