I was confused in the terminology so I asked a Magnaflow Tech to tell me the difference between a muffler and a resonator. This was his answer:

""Mufflers and resonators are one in the same. We use the term resonator when two mufflers are used in line of one another."

When I pulled the original style resonators off of my Challenger, I was surprised to see a "straight thru" design. It was an oval shape so it would have more noise suppression than a glass pack type (round) style of muffler in that location.


The round straight-thru mufflers will not have as much noise suppression as the round "chambered" style. The chambered style will be more restrictive than the straight-thru style. So it depends on what you are after. The space that you are wanting to add a muffler is very restrictive, so a round muffler is about your only choice.

I have read that when trying to stop a droning noise, a second muffler (resonator) is used to break up the sound waves. Adding the second muffler will also change the sound depending on the selection of muffler.
If you want to change the sound of the exhaust a lot, then you may want to start over with your existing muffler selection. If you want to quiet down the exhaust a little bit, then adding the second muffler may do that. Then the type of muffler will then determine the final loudness and the performance level.

It appears that you might end up with two mufflers per side due to the size of the exhaust, the size of the engine, and you do not want to lose performance.