I used one like this. It quieted it down a good bit. Still loud though, so might be just what your after. I get a lot of compliments on the sound.

https://www.summitracing.com/parts/mpe-14419/overview/

 

Throw on a zzp resonator section. I'm running catless downpipe and a resonator with muffler delete and it sounds really good. Not too loud

 

thats pretty much how my exhaust is too. im sure the zzp resonator will quiet it down a bit more then my turbo xs resonator. my car still roars under boost.

 

I have a MPX catback I could sell you. Im in PA

 

I have a magnaflow muffler. Its quiet though. It's very close to stock.

 

I just installed ZZP's Catless Downpipe. So now I'm Catless DP with the Resonator and Straight Pipe all the way back. On warm up the car is unbearably loud, my neighbors expressed their anger. But driving it's glorious. You let off the throttle and just listen to all these cracks and pops, when you're on it you get this amazing noise and when you shift a nice heavy crack. I really really like it I just have to figure out a better place to park so I don't anger the neighbors in the mornings too much. This is on a 2009 Cobalt SS/TC