Advice for anyone doing there own muffler swap - (I've done mine with a Flowmaster Super 40 muffler) - the rear hanger clamp may not line up under the hanger bracket on the truck if you don't add an extension pipe to the rear of the muffler.
The rear exhaust hanger rods are welded to the Ram OEM muffler and when you cut the pipe behind the muffler whether at I" or 2" (I left 2" on muffler if I ever wanted to remount OEM muffler) the new clamp at the rear of the new muffler clamping the muffler to OEM existing 3" exhaust pipe will be back a couple of inches and not directly under the hanger bracket on the truck. The rear of the muffler will be directly under the hanger bracket if you mount the rear of the new muffler directly to the rear cutoff pipe.
The Mufflex-Performance Exhaust instruction show mounting rear to existing cutoff pipe and using hanger clamp to clamp the muffler to rear pipe - won't line up under truck hanger bracket.
When I replaced my muffler:
I cut off the OEM muffler pipe 2" in front of the muffler and 2" after the muffler to leave pipe stubs on each end of OEM muffler in case I ever wanted to reinstall it (just clamp or better yet, weld back if ever needed).
I attached the new muffler directly to the front cut off pipe (3" muffler end slips over 3" pipe) and added a 12" stainless steel 3" pipe (Flowmaster Super 40 length is shorter than OEM muffler) slips into rear flange of new muffler and connect to rear cut off pipe.
New 3" stainless steel clamps at each end of muffler and 3" stainless steel clamp at new pipe to truck pipe connection. Will eventually replace clamps with permanent welds.
Requires a new hanger clamp with double hanger rods to attach to new pipe behind muffler to hold up rear of muffler and front of dual exhaust pipes. I have not found a good stainless steel hanger clamp yet so I temporarily used a steel hanger clamp that I will replace when I find a correct stainless steel hanger rod clamp.
The rear dual exhaust pipes/tips need to be kept lined up and in correct elevation when everything is put together.
I really like the sound of my new Flowmaster Super 40 muffler - has a great low deep rumble. Not too loud to be obnoxious --- the 2019 Ram EOM resonators really mellow out loud exhaust.
This is the photo of the OEM muffler removed from my 2019 Ram Limited - see hanger location