the other side of the coin is theres deleets and then there's deleets, mine keeps the cat, but removed the failed, wildly expensive , complicated, and impossible to service
at home "emmisions" stuff, no smoke, no noise, runs nice, gets a bit better milage.
You can notice the nox smell a bit when its cold, but it cleans up after a few minuits, and stays good all day.
What you will hear true gear heads say comes out of the exhaust pipe, is "nothing but heat", and its true, with a realy well tuned diesel making
lots of power, you can see it, mass heat ripples coming out of the pipes, you will see the same thing from aircraft exhausts, the other thing true gear heads will say is that "all noise is proof of ineficiency and wasted power"
just saying