don't forget to release the pressure w/ a rag over the schrader valve. The rails and injectors can be hard to get out/off...takes some tugging some times. When you put your new ones in, be sure and lube the o-rings w/ vaseline or something to make it easier to slide them in...if they're new, I don't know if you have to do that, but prob. wouldn't hurt.
Are you buying bigger injectors? I'm sure you know if you change injector size, you also have to recalibrate your MAF or buy a new one.