I have been using the Hypertech programmer for almost 10 years. They are pricey, but the current programmer lets you pick three different settings. You see an immediate boost of power once it is installed and mileage goes up as well. I noticed the turbo kicks in sooner and torque is increased. It you change the size of your tires it will allow you to input the size to correct the speedometer.if you take your power stroke to the dealer or go in for a smog check (California) you need to return the vehicle to stock settings and that takes less than 5 minutes. After the service is over, it takes about 20 minutes to reprogram.
Good luck,
Mano