I tweaked my pump, as I was getting white smoke and I now get little black, but it has made no difference to the amount of power. I think there is another adjustment on the pump but I have only heard bad things when people have had a play with them.
I have also only ever known them as core plugs.
Apart from the obvious one you can see I think there is another behind the timing case. To change it you have to remove the timing case, water pump etc.
You should not need a tow start to bleed the lines.
When I changed one of my injectors I just:
1. used the small leaver on the bottom of the fuel pump to re-pressurise the fuel system
2. put a rag round the bleed line banjo bolt
3. loosened the bolt to let the bubbles of air out
4. tighten...