Just a quick thought. You can buy a "Dent puller" for about $20 at Autozone or Pep boys (most likely cheaper on the internets) and easily pop out most dents in the pipe. Also if the crack in the pipe is not too wide, flowing some solder into it can seal it up and you can use "Liquid Metal" EPOXY as a temp patch but it will need to be redone after a few rides as the heat usually breaks it down. Anyways, Good luck with the tuning I am so jealous of your project