I think the dremel tools work best, the cutting wheels and a flex line off the base work great. Being small helps with accuracy and are very controlable. If you have pneumatics in your shop, air tools are an option. Either way, a cutting wheel and a steady hand are what you need. Not sure what you have in mind, but snips are going to be very difficult and will very likely cause cracks. Tape off the area to be worked beyond the well beyond the cut lines, draw your lines over the tape. This is finished material, so it's very unlikely it will not be without any accidents during the process.
Maybe find some wrecked sportbike bodywork and practice your cuts there first to see how the tools handle and become familiar with their operation.