I'm not that knowledgeable when it comes to turbos. I would have to imagine that modifying the exhaust from turbo back wouldn't make that much of a difference, and it's more that you are seeking a change in sound? Perhaps if you were to add a performance chip then the exhaust would be more beneficial, right? For me & my wife the attraction to the modern day diesel is it's less noisy and we want to keep it that way.
My 2005 Ram Hemi was loud, I'm with you enjoying the quiet, so new exhausts are not for me, however, there are performance gains to be made if loud is ok?
Generally Cat-Back exhaust change the sound so slightly you can't hardly tell. When you remove the DPF and other big restrictions is where it becomes noticeably loud.