Forgive the ignorance, what is "deleting"
Getting rid of the emissions equipment on your vehicle. The first and most common one to do is getting rid of the whole exhaust system; the Catalytic converter, DPF, DEF system and the muffler also. It lets the truck breath (actually this would probably be more like exhale) easier. Opens it up. They replace all of that with just a straight pipe usually, or straight pipe with muffler, like this one from Flo-Pro:
http://dalessuperstore.com/i-238945...e-2016-2017-2-8l-colorado-canyon-duramax.html
The other remaining thing that people delete, but don't always do it right away, is getting rid of the EGR Cooler. That also helps with the breathing. Some people just disable and leave it there, which can be ok. But I believe air still tries to go through it, plus it holds coolant. So, if it ever got a leak, it could leak coolant back into the engine I believe but I'm not positive where the leaked coolant could go. Here is a kit for that:
http://www.xtremediesel.com/oz-tuner-oz-col-egr-kit-egr-race-track-kit.aspx
To do all this though, you can't just rip all that stuff off there. If you do that and then fire the truck up, it's not going to like it. Mainly, the ECM (Engine Control Module) is not going to be happy. It will see those units as missing and put the truck into limp mode, or just shut it off all together probably. You have to get a tuner to tell the computer that those parts still exist, even though they don't. Also, tuning rewrites the ECM and adjusts how the truck runs. If you get the one listed, or their counterparts, you can switch power levels (4 of them) on the fly. And unfortunately, not all tuners do that, you have to get the right one. I know there are a few out there that do it, but I know this one for sure does, from MotorOps who is DuramaxTuner's Canadian counterpart:
http://motorops.ca/duramax/duramax-tuning/2-8l-duramax-canyon-colorado-auto-cal.html
However, many states frown, or scowl, at you if you delete your emissions. They put it on there for a reason, but unfortunately, it can cause issues. As some of our members have found out. And the easiest way to fix it is get rid of it. The DPF and EGR are undoubtedly going to plug up and get full of gunk eventually. Now, that will probably be around 150,000-200,000 miles or more, but it will happen. And that will cost you a couple thousand each probably to repair. The above-mentioned delete items will run you around $1,600 I think, but my math might be off. And that's a 1 time and done. If you do it, you need to get the tuner first and you can turn off the stuff and leave it there, until such time as you can afford to buy the delete items. You should see performance gains, MPG gains, cooler running engine timeps with doing this as well. Should sound better too, even with putting a performance muffler on it.