I was comparing the new washer to one of the old ones, and I noticed the new one has a slightly smaller circumference, and it is slightly curved. I am assuming the curved side goes down toward the bore, but I think once tightened it is going to be flat no matter what because the old one is flat. Probably don't matter. But I am contemplating my first move on removing the washers. I did find out there is a special tool specially designed to remove them. If this tool is used you need the center opening to be un molested to grab it correctly. But it has to be ordered, about $75.00 I have purchased a new screwdriver $6.00 and I think it will do the job. If I could purchase this tool locally I would buy one and add it to my collection. So far no one around here has one on hand. After looking at the pic of the washers I can tell the used one is larger simply because it was tightened and it stretched, well maybe.
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W T F...all talk no link to special tool...*** is that about...

U did not need buy a new screw driver...a freshly ground one would work...but maybe cheaper buy screwdriver n a grinder ...
yes the idea is that is a gasket and compressed under torque load and seals the injector in place. In compression it gets twisted and compressed at the same time so there is shear force on the gasket.
Hope u manage to get it out without too much difficulty.