If you run the nozzles in the rubber couplers you might have clearance issues with the fuel rail or injectors. I am in the process of doing the same thing. The best bet IMO is to get a extra intake manifold and do the install on a good level surface, and test spray direction on a bench. I know there are some metal inserts that you can use to screw in your N2O nozzels. I am planning to do the nozzle placement on the intake runner itself away from the fuel rail.