There was a post on here somewhere where someone photoshopped the back end possibilities removing the exhaust. Sorry I don't know where it is. I think it involved running a diffusser(sp) across that area.
As for Cobra side pipes that was my initial thought as well, some late 60's Vettes ran that type of side pipe as well. There is also a thread on that subject where various side pipes were photo shopped onto the Crossfire. To my knowledge no one has actually done side pipes as yet.
Pat