Getting rid of the carbon buildup is a good idea by itself, so I think I will have to do that. I don't want to shoot myself in the foot with this.
I'm more worried about cleaning the injector bore. I'm not sure if it's all metal, and I have a feeling it's not right around the level where the injector has the rubber ring, cause it sort of pops into place at that point. I'm concerned about which brushes etc I can use but since it doesn't look like anyone has had to do this, it looks like I'll just have to wing it!