A dremel may fray the carbon, but a small coping saw will work well. Yes you will have to pull the cans apart, especially since the center tube may be bent. You can get new insulation at cycle gear pretty cheap in their dirt bike parts area, and it works great. The rivets are aluminum, just measure one once you drill off the head and pull it for the correct size. Be careful with the center screen so you don't tear it skiing it off the cut the center tube. Wrap the insulation around the center tube and screen tightly and secure with masking tape, then slip the carbon housing over. Then add the end caps and rivet. It's also a good oportunity to buff the cans with fine steel wool and have the clear redone, it's about 50 to 100 bucks at your local body shop. You can get new stickers from motowheels.
Sorry about the typos, I'm on my phone