any reason to keep the rear cat 3.4

so my recent offroading adventure took a toll on my already leaking exhuast, the flange after the cat and before the muffler is tweaked to hell, thus i have a large exhaust leak that will leak until new flanges are installed.

which brings me to my question, since i might as well modify my exhaust to get the most clearance, why not delete the rear cat and connect the muffler and tubing straight to the front flange.
would there be any gains/losses or is it not noticeable to tell one way or the other?
id imagine the sound would change a bit.

If deleting the cat, would it be better to keep the exhaust 2.25 to the muffler and 2.5 out? or run 2.5 in / 2.5 out?

Im frequently going up the mountains 10k ft+, if that matters at all.