The way tuning works is a new firmware, or tune, has to be loaded onto the Engine Control Module (ECM). The ECM is a computer that runs the vehicle and makes adjustments in real time to maintain manufacturer specs for the vehicle. It also controls what happens when a fault is experienced somewhere in the vehicle. In the case of the DPF and other emissions equipment, the ECM is programmed to respond to a fault in that system by giving warnings and then ultimately putting the vehicle into a reduced power mode that is basically a crawl.
To circumvent any of the emissions equipment,new firmware has to be loaded onto the ECM. This is what we call tuning. The ECM is being tuned to operate within different parameters to achieve different operating specs for the vehicle.
So, to remove the DPF, DEF tank, or EGR, you would need a tuner to write a tune for your truck, then upload that to your ECM, then you can remove those components.
But here's the rub: This is all federally illegal and the EPA is literally knocking on doors here in the US to shut down any and every shop that is performing these types of mods on diesels. If you do a quick google search, you'll soon realize that it's about impossible to get it done via the internet in the US. There are shops still doing it, but you have to know someone usually.
That being said, our neighbors to the north are not subject to the EPA and tunes (good tunes, from my personal experience) can be found there still. The hardware I haven't looked into, so you'll want to do some digging or ask the tuner you go with where you can get reliable delete pipes right now. Ebay is probably not a good idea; most everything I have seen on there as of late has pretty inconsistent and bad reviews regarding fitment.
Good luck with whatever you decide to do.