I got better mileage after I installed one on my 03 4WD crewcab. But it could have been that the increase was due to the engine breaking in as well. Certainly didn't hurt the mileage and the performance improvement will make me install another on my new truck.
Just bought an 04 w/ LB7 engine last week and my programmer won't work. HyperTech says they will reprogram to work for $200.
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