I just installed a Wicked Flow Racing muffler -[google- Bear river converters-under mufflers]. Nice low rumble, really nice snarl on WOT, and Not loud inside car. It's a straight thru muffler, and I can tell it helped the pickup.
Well built, beefey, and sells for $45.00.
Friend on mine that has muffler shop, turned me onto this muffler. He is also a long time race car driver, so he knows a thing or two about exhaust.

 

just loaded a video of driving from work tonight. Short 3 min vid, Basically factory exhaust except for small straight through muffler- http://www.youtube.com/watch?v=SWrWMtyoDq0 . It might be still "processing" if it does not play for you.

 

I installed the New Magnaflow Exhaust back in June; once installed, you no longer have a resignator. Everything comes off/out'; 3" front to back. I have no issues with the sound. It is fricken awesome. Now, yes the "bassy" low Hmmmmm sound is more prominant, but damn it sounds good. There is no 'weedeater' sound at any RPM. The sound is not aggravating at all. It is never too loud. However, I will say that at 80mph, it is a little louder than expected, but nothing I would get rid of!!!!
"Sounds awesome. The higher the RPM the more different and better it sounds.

 

You should turn off the comments . You already got some idiots leaving Smart @$$ comments

Doesn't sound to overly loud. Would like to hear how it sounds inside @ WOT.

P.S. Sounds like the roads you drive on have seen better days..sometimes it sounds like you on a trolley track

 

I will post an"outside" and wot vids soon, I am so loaded with work right now. I will try to figure out how to disable comments. On the side note- buyer's remorse is kicking in, - this freaking thing is giving me such a headache. So I am looking for a proper small muffler ( like on that magnaflow exhaust mentioned by another member^^^) or Vibrant super quiet resonator. Arghhh

 

From my post #6 above. This is your best bet until/unless you go back to a chambered muffler...

 

Just get a DP for the HHR SS

 

...and finally I can answer the original question of this post with this vid: http://www.youtube.com/watch?v=9njfZuOocSo . So, today I went back to the car-x and got them put my factory muffler back on, but remove the resonator and replace it with the 2 foot long piece of straight pipe. The result is basically stock noise level or perhaps 3 to 5 % louder and when let the gas pedal off- it makes this faint barely audible popping sound. Also it seems to have a little more response when flooring it. And another observation: in last week of me dealing with the car's exhaust I am amazed how sooty this GM engine is, I mean it is diesel -like sooty. It got my new muffler covered in soot inside in just one day. And today I was looking inside of the freshly removed resonator and it is like a charcoal inside. I am wondering if this pipe is able to basically move all this soot along to the outside or we gonna see it accumulate inside for years and create some blockages :-0

 

I like the way my SS sounds with just cleaning out the stock cats so the stock exhaust is cat-less. Its slightly louder, no drone or rasp, and very clean.

 

I believe the soot is from the turbo..it causes the exhaust to cool faster before it has a chance to burn off completely.. its just like a torch thats set rich, really sooty till the heat gets hot enuf to burn it off..