Might be time for a new cat.
 

Cat is starting to rattle so it's probably time to get a new one. I've been throwing around the idea of replacing it with a resonator. How's one sound on there? I've read it cuts the rasp and makes the tone deeper? Car has stock manifolds and a dynomax cat back.

It will probably make it sound better if you get an good sound deadening resonator. the Cat actually works as a resonator blocking a lot of rasp. you will need something that does more than a Cat to see a reduction in rasp. I'm currently looking at a Auger style muffler insert to see how well it works.