I think tbe muffler delete should be ok as long as the tailpipe clears the floorpans, or has a real good turn down.
4Runneree had can openered the stock muffler and turned my cabin floor into a megaphone, hurt my head after about 2200 rpm even as a lad of 23 years old. I cut out the muffler and used the remaining tailpipe and clamps to fabricate a side outlet. I drove 4Runneree another year with that setup and was just fine with the tractor-like exhaust note. Cabin noise was essentially cured with the side pipe.