Mufflers are parts for your car that do more than just look nice, they also can make it sound better or give you more torque.  There are mufflers, muffler tips, and exhaust which are all different

This is a muffler equipped with a silencer.	This is a DC, stainless steel, cat-back exhaust.
These are DC polished headers.	These are turbo mufflers each equipped with a silencer.
These are two mufflers without silencers.	This is another muffler with a 2 inch silencer.