[CaptnJohn]

If never going to tow over 10,000# a gasser will struggle on big hills but will work. The 6.0 and 6.4 engines Ford bought from others were never a good idea. A delete is expensive if complete and done correct, not really worth it in fuel savings (about 0). That money would be better spend on a newer engine. When it comes to trade no dealer will take it unless nearly free to send to auction. The emission items are required by federal law. In at least CA deleted will not pass the smog test, not a test in many states.
I had the chore of driving my neighbors 2018 GMC 3500 pulling 12,700# over 1650 miles. I'd not trade him for my 2016 F350 with over 80,000 miles on the odometer. The GMC got a very little better mileage single, my F350 gets better towing 2000# more weight ~ also a full profile vs mid profile. The GMC did seem to have a little stronger engine brake but nothing else was impressive.