Never looked under a TCH but if you have room for the 2nd muffler this is what I did:
http://www.toyotanation.com/forum/t137210.html
Left muffler 17440-31010 $150.13
Bracket 17509-31020 45.47
Insulator 58328-33010 36.97
Gasket 90080-43028 1.24
Cutout is easy. Make a paper pattern of the right side. Hang the 2nd muffler and mark the center line on the bumper cover. Transfer the paper pattern cutoff to the bumper cover. Use snips and a dremel to cut to the line.
I did have a V6 bumper cover put on later after I got rear ended but it looks the same as the one I cutout.
click on pic to enlarge...
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