I bought my 07.5 with the dpf delete, and it was quiet. I deleted the muffler shortly after I bought it, without a noticeable change. I just got rid if the downpipe cat for a 5" downpipe due to the longarm kit I am installing this week.
I took it for a drive with just the downpipe and it is nasty LOUD! I am probably going to have to invest in a muffler for it. The truck goes in for the Longarm kit Wednesday and I am going to run just the downpipe til then, hopefully I won't get a ticket before then!
I probably will get the exhaust extended to the back of the cab for the time being, hopefully that will lessen the noise(at least in the cab)

 

i did turbo back right off the bat so mine was alot louder

 

Here is the outlet end of the DPF if you were wonderin.. Nice and clean for sure.

But you can't fool the system by bypassing it. I don't know how much noise you guys want really.. I found dropping the DPF/Cat was enough for a little increase in sound, not as loud as my 97 with a MBRP system. I am not a fan of straight pipes really, just too much noise for daily driving and towing.

 

Mine is straight piped with 5" and it is loud, in summer I usually put the muffler back on because the cops have their windows open LOL

 

what did your 85 over cp3 cost powerwagon