What brand are the pipes? If you can find that you may find fitting instructions on their website, which can give us a clue about those clamps. I suspect you're going to have to take a cutting tool to them, which will be the quickest, if you have a junior hacksay or dremel.
"High" temp paint really isn't very durable. Ceramic coating, that's what you want. (Have them coated on the inside as well.) Your bike will be A LOT cooler to ride.