I have done this before and gotten by with it. At your convenience and when there's a few extra bucks in your budget, order four glow plugs from the parts shop here. They have a better price than what you paid. It will take a little time, but you will have them, and you can replace them at your convenience. It will take some time to put in the rest of them. The back two are particularly hard to get at without pulling the injector lines(I call them "the spider". Replace them at your leisure and then you'll be in good shape.