Did you have a thread on any fuel injection issues?

If you're already sold on the injectors, we really can't help you.

Pop testing allows a person to know the exact point (psi) where the injector opens...........it's preferable that all six be quite close to each other for a smooth running engine.

There are certain risks in changing nozzles...........sealing the nozzle to the holder is an issue...........there is no gasket. Additionally, it would be very rare to have a set work properly without checking and adjusting the pop pressure after the new nozzle is installed.