I installed a new Cold Air Intake on my 2019 GMC AT4. This was an easy process taking less then an hour with simple hand tools. The process should work for any GMC/Silverado Truck with a 6.2 liter or the 5.3 liter will be the same process. I hope this helps you to find the parts and install you need.

After I installed the CAI I took it to a local GMC dealer and they used the labor code and did all the programming to make the sensors run with more air. This change of exhaust and CAI will increase your horsepower from 420 to 435.

The GM Cat Back Exhaust and CAI add on is $2200
I installed my Flowmaster 40 Muffler for $250
I also decided to change out the tips for a sportier look and the tips cost $50
Both the muffler and tips were installed at a muffler shop video below.
The Cold Air intake with Shipping was $500
I installed it myself and when you buy it from Chevyparts.com you get a labor code supplied for the programming the ECU is included.
This means you can do this yourself for around $800 saving yourself around $1400

The exhaust video is here
   • Flowmaster 40 Exhaust and Chrome Tips...  

The Cold Air Intake can be found here with all the details
https://www.shopchevyparts.com/perfor...

Hope this helps you on your decisions or installs.