O-Rings. Relieve pressure at schader valve. Remove the 4 bolts that hold the rail. Remove rail and injectors as a unit. Remove injectors one at a time and replace orings, install back into rail. (You don't want to get the electrical connections wrong). I use Vasoline on my o-rings. When you have all the injectors in the rail, install the whole shebang into the intake, rocking back and forth and wiggling/pushing. I like the Mopar o-rings. I've been having problems with leaky i njectors and the o-rings that come on the replacements don't fit as tight on the inj., making it harder to install.
Freeze plug. Like they said. If you can get to it, don't remove more than you have to. I drive a sharp punch into it, and pry it out. Install new one with a big socket. Put Permatex on it.