Installed Zex NOS set to 65HP on 2000 s2000 w/13k miles. What other modification are available to insure proper fuel delivery. I would like to go to 75HP. I want to get this right the first time. Also, what aftermarket parts
( higher flow ) ie Throttle body, fuel injectors, fuel pump,... would you suggest.

Any help is appreciated.

 

Since you already have the system installed, I'll save the lecture on how bad nitrous is for the S2000 in the manner in which you are using it. I'll also spare you the story of a local S2000 that has about 2500 miles on the 3rd engine using the exact same ZEX 75 hp setup that you are going to. The ZEX kits aren't producing the numbers that the other big name systems (ie. NX, NOS, etc.) do so there is very little difference going from the 65 to the 75 shot. The one locally that I'm speaking of dynoed almost 50 hp gain at the wheels with a 75 shot. Your stock fuel injectors should be sufficient as should your stock fuel pump. The problem with the system is that it is too difficult to ensure proper distribution unless you're using a direct port set up. I would also consider shopping for a clutch. Your's probably won't hold up very long once you start 'squirting' regularly. Good luck.