My 5.3L 2012 GMC Sierra before and after getting it custom tuned by Lew (http://www.diablewtune.com/). It's a DiabloSport Trinity T1000 tuner. Kicks nice and hard during shifts now. Hit 120 MPH before having to let off. She could have kept going too. Video was taken from the back seat behind the driver

Performance upgrades:

TruckExhaustKits.com
2.25" Aluminized Steel Dual Exhaust Kit
Ebay.com
Flowmaster Super 40 Series Muffler
Dual Inlets 2.50", Dual Outlets 2.50"
AutoAnything.com,
K&N 77 Series Metal Intake Kit
Diablewtune.com
DiabloSport Trinity T1000 tuner

Check out these other videos of the truck:

Sound of before and after intake install:
   • Before and After Installing a K&N Col...  

K&N Cold Air Intake Installation:
   • K&N 77 Series Cold Air Intake Install...  

Exhaust Sound Flyby's and Hard Acceleration:
   • 2012 GMC Sierra Exhaust: Flyby's and ...  

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