Ah, very nice. I see the bolt preloads the spring which puts pressure on the diaphragm. That bolt looks interesting. Looks like you can bore out the center and use that instead of having to do a separate piece. Would look nicer that way.
BTW: I drove around with my stock FPS and 17.3lbs injectors and floored it once it was warmed up. No signs of the engine being lean that I can notice. In 4th, if I get it to 3000 rpm, I can accelerate up a mild grade and it feels find up to 4000 RPM. Tried a steeper incline and was able to hold 40 in 4th at over 3000 RPM. I'm using these as baselines so when I swap the FPS I'll be able to see if there are any differences.