I know that putting on headers would increase performance (hp and torque) but how about sound? I am planning to get some headers however, I would not want them if they were obnoxiously loud at low RPMs. Would my idling sound change as well? Appreciate the input!

 

No clue on sixxes, but on an 8 it does change the tone for the better in my opinion. Any change you make to the airflow of the pipes will alter the sound that is put out.