What are bungs?
Bungs are threaded holes in the DPF & CAT Delete pipe to accommodate the EGT, Oxygen, NOX & Pressure sensors.
Do I need bungs?
No, but for appearance reasons you may want them. DPF delete capable tuners produced today no longer require sensors to be plugged back into the exhaust system. All of these sensors are disabled with programming. These brands include: H&S Performance, Spartan, SCT, EFI Live & RaceME.
Reasons for bungs
If your state has stricter emissions laws (CA, NY & CO) you might consider a DPF delete kit that has bungs for the factory sensors. A quick glance under the truck to the untrained eye, it would appear the factory emission components are still in place. If you'd rather not have wires hanging under your truck or tied up using zip-ties it also makes for a cleaner look.
The demand for DPF delete systems w/bungs is so low that Flo-Pro recently discontinued all there DPF delete kits with bungs. As a company we sell DPF delete pipes without bungs 10/1. So from our experience, industry trends and overall popularity no bungs is the most common.
A word of caution
More often than not; when attempting to remove sensors from the factory DPF the threads are stripped. With two different metals (sensor & pipe) and the DPF delete pipe constantly heating up and cooling down its conducive for stripping. If you decide to re-locate the factory sensors, soak the fittings with penetrating over night to help with removal.
Deciding to install a DPF delete pipe with or without bungs is a personal preference. If you want a clean factory look, are willing to spend a little more money, don't like the idea of sensors and wiring harnesses tied up under your truck and are ok with the little extra effort, then by all means get a DPF delete pipe with bungs.