i like the dynomax super turbo mufflers. have them on my dart. quiet but not too quiet and they have a nice deep tone. they needed some miles to get a good sound though. it was way too quiet at first but i really like it now.
abodyjoe is right. These mufflers have a nice rumble at idle(not loud) and really deliver a nice growl at high RPM. I had them on my truck & I really liked them! They are a bit on the spendy side though.