Ripped mine off my coupe due to rattling. It made the car growl bit louder, in a good way though, like you have an aftermarket intake. That's the louder sounder people hear and its because shield also muffled the sound of the exhaust. I just bought some exhaust heat wrap and wrapped up the same area to mitigate the heat and dry grass issue. But there's no performance issues is taking it off.

 

 

When I replace my cats (high flows or test pipes, don't know yet) I'm just going to spray them with the silicone exhaust paint and then wrap them up. As of now to floor gets warm enough as it is, so I might fabricate some sort of heat shield up in there as well.

 

My 04' was from a salt state and when I bought it both cat pipe shields were rusted and making tons of noise. I just cut them off and haven't had any problems since. You won't find too many shops interested in trying to weld old rusty metal. You would probably have to cut the rust areas out and add in new metal which would just cost too much for an old set of cats. Honestly I would just order a set of test pipes and weld in hi flow stainless bullet cats on each side to replace the old ones if yours are really really bad.

 

Just fixed my rattle. Simple fix.
Look for a loose hose clamp.
Adjust / tighten or replace.