I just recently acquired a 2008 HHR Panel LT 2.4L and want to replace the muffler to beef up the sound. I'm looking for a deeper throaty sound not that raspy bee buzzy sound. Someone recommended the Flowmaster 40 series and I've checked it out on YouTube but it seems to sound different in every video.
Is it possible to get a good sound with just a muffler?

 

Yes, I have tried a couple, the 40 will be a tad large for the space. I found the Flowmaster HP2 shorty's fit great and sound very throaty, nice rumble, but no drone. I am very happy with them and 3 other SS owners agree, it sound sweet.

http://www.flowmastermufflers.com/sh...&orig=12412300

 

A lot of your difference in sound can come from pipe diameter and other restrictions, such as resonator and catalytic converter. Just for a daily driver and in pursuit of good deep sound without a buzzy high pitched note id recommend no larger than 2.25 piping, an 18 to 24 inch glasspack or aftermarket resonator in place of the stock resonator and either a magnaflow or flowmaster hp2 ie hushpower 2. Both of these seem to provide good solid tones on small displacement engines. I've ran both on my personal vehicles. This is for naturally aspirated engines as the lnf can and does need more flow capacity due to exhaust pressure and engine load. Don't overlook also that different intake setups can and will affect your exhaust pitch and tone. I've noticed differences even in filter media changing my exhaust sound.