Hello Calder,
I have a 14 3500, deleted couple of years now. Dealer said DEF ruined catalytic converter, believed them, and dollar for dollar chose to delete. No testing where we are. In my delete, I had no noticeable difference whatsoever. I used very little DEF mile to mile, more towing which is to be expected. Another consideration is that according to dealers, by law, they have to restore the emissions to pre-delete, costing you seriously a second time if you choose to trade rather than an outright sale. This is just my two cents, I wouldn't do it again.
When taking truck for recall, I was told the converter recall was still outstanding. Dealer changed hands since initial visit, new dealer ordered converter and loaded it in the bed of the truck to clear recall. If this is your situation I know where you can get one inexpensively.