Honestly not sure if there's enough room... but could a mufller fit longitudinally?
If you size the muffler properly, a quick bend behind the differential, fit the muffler front-rear tilted upwards, tips installed on the outlets.
The minimum size Mangaflow offers has a case length of 14". Total length with inlets and outlets is 20". I imagine that might fit with some coercion.
LINK
With regard to melting things, it's simple enough to cut the mesh and weld a ring into place that leaves sufficient room for the tip to jiggle (3/4" clearance or so, if mounts are fairly solid). Heat shields or a wrap would be nice, but it may not be necessary with how open that design is. We shall see.
Thanks for being innovative, @
sw20kosh !