You have to pick a lane...

1) Leave it stock and continue to put filtered cow piss in the DEF tank.

Upside: Every dealer will service it no problem.

Downside: DEF & clogged particulate filter$$$, shorter engine longevity

2) Pull ALL the emissions crap off if it and buy a good programmer/tuner.

Upside: More power, fuel economy and no more DEF bs, longer engine life

Downside: Most dealers (right now anyway) won't touch it. They're not equipped to diagnose anything outside of jacking into the ALDL and running diagnostics. AND in many cases, your warranty is voided.

Other downsides: Unintentionally rolling coal, nasty acrid diesel smoke when cold/starting up in winter, increased "smells like an old diesel" smells. Truck, depending on what it is, will be worth less. You won't even get trade-in book value since it'll most likely either not be taken on trade in or go straight to the auction. They have no idea what they'd be getting with no factory diagnostics.

One more: You're going to hurt it or blow it up with no torque management.

Then there's the law of unintended consequences: Every little dbag who gets a diesel will be yanking the emissions crap and rolling coal EVERYWHERE. Yeah okay, I'm all for more power, but I sure as hell don't want to be smelling that bullshit or see black clouds all over the place... Same with non-catalyzed gas cars...I REALLY don't miss smelling and TASTING raw exhaust (unless it's race gas...yum) but seriously... just leave it the hell alone. And put mufflers on your truck asshole...loud is just annoying AND it actually makes less power...

If you're a good mechanic and know how to program without blowing it up, deleting might be okay IF and that's a BIG IF you're going to keep it until it's ready for the junkyard.

Otherwise... you need to ask yourself of you really want that in your life - a Frankenstein, no dealer will touch and being completely ON YOUR OWN to figure it out when it breaks. You have to think about it.... it's very similar to a classic car or hotrod. It's most likely NOT going to be "stock reliable" because unless you can control yourself, you're going to do dumb shit like cranking up the boost too much and kill the motor OR wipe out the transmission 2 weeks after you delete because you've got a lot more power now...

AND... very few understand the fact that they put a SHIT TON of torque management into the stock tune to A) Keep you from wrapping it around a pole and B) To extend the life of the trans and rear. These turbo diesels are advertised as having WAY more power than they REALLY DO on the road, because they pull so much out of it to keep it together...If you start messing with that .... that's when the teardrops start fella....

Don't say nobody didn't tell you...

The DEF dependent diesel pick up trucks can be reprogrammed (chipped) to not need DEF fluid.