Do I need a new muffler?

A new muffler? Depends on the car -- OEM-style ones are more expensive and designed to fit your car's unique shape. Generic ones are cheaper, but may look awkward and are intended more for trucks. If you drive a standard sedan, you'll notice your muffler is a special shape right at the back bumper, and so it can cost around $150 for a replacement muffler. Trucks have the muffler towards the middle and have plenty of under-body space, so they use a generic oval shape and just have the pipe extend to the end... these universal mufflers are much cheaper, closer to $50.  more