Ok, friend of mine has a 08 6.4. Put the sct extreme in it and noticed no difference except it shifted alot harder. Put it back to stock and it seemed to run better than tuned. Does the pyro HAVE to be hooked up for the programmer to work properly? Put the truck on the perf tune and still had no luck, kept blowing smoke out of the engine compartment. Turned it back to stock again. Do you push the circle button to select the tune or do you have to push escape?? Frickin thing takes forever to download. Please let me know!