[Charlie]

The exhaust baffles mentioned earlier could be the Car Chemistry brand inserts that Summit Racing sells. You can get them in various numbers of discs and through-pipe diameters, but I have never tried them so I can't comment on their effectiveness. I really doubt they do very much good, but who knows? Maybe someone else has tried them in their Cobra and will share his opinion.
Another type of insert I have seen is the spiral baffle type. Again, no personal experience, but some people have tried them.
The third type, and probably the most effective sound control, is the Hooker Header baffle inserts that fit into their side pipe systems, but you can buy the inserts and slip them into your own side pipes. They also have a glass pack insert.
I have glass pack cores (not Hooker) on mine and they are LOUD! I think, too loud, but my Cobra buddies all like the sound of my car.