The best puller I've used is constructed and works like this: Get a nut that will thread on the top of the injector. I know I've seen the size posted here a dozen times but I don't remember it. Do a search or maybe someone will pipe up.
Get a piece of 1" diameter electrical conduit, or maybe a similar size piece of PVC. Whatever will just fit over the injector and rest on the head. Remove the hold-down nut on an injector (there's a small square-cut o-ring dust seal between the hold-down nut and the injector - reuse it if you can or replace it on the new injectors). Figure the length of the tube required such that as it sits over the injector and rests on the head, a few threads of the injector will stick through the other end. Cut the tube at this length. Put your short piece of tubing over the injector. Thread the nut on. As the nut contacts the tube and presses down on it, which is sitting on the head, it will pull on the injector. As you continue to tighten down on the nut, it will pop the injector right out.
Piece o' cake!
Other than that, do as mikel said, keep everything clean! Go to the carwash and spray off everything good around the injectors first.
You don't have to completely remove the injector lines, but you will have to remove many of the clamps and maybe the valve covers so you can push them out of the way. But whatever you do, don't kink them! They are very hard and stiff, but if bent, they will need to be replaced. The choice on that is yours.
Yes, use the thinnest washers.
Once installed, leave the hold-down nuts on the injector lines slightly loose and have someone watch for fuel weepage as you crank over the motor the first time. Once they are all getting a little wet, torque them down, blow off the excess fuel with compressed air, then fire it up!
Then go for a drive. Wheeeeeeeee!
-Jay