ROFL....... sorry
Sure, you can install the air dam. Not sure if you'll be able to measure the fuel savings though.
There are other items that are more effective for increased fuel efficiency.
Proper tire inflation
No extra weight that is just along for the ride.
Easy acceleration
Coast before braking. Anticipate stop lights.
Speed. These trucks get best fuel mileage around 65-70 mph.
Clean air filter.
Engine maintenance.
My good ol' 1FE-GR (4.0 L, V-6) with an Automatic in 2wd will consistently give me 20-21 mpg running at 70 mph. I don't bother with fuel mileage in town.....too many variables.
There is a whole market of doodads that claim to give more power and better fuel efficiency. Such as CAI, bed covers, exhausts.........all sorts of add-ons. Be very skeptical of any claims.
The engineers who designed these trucks go through great trouble to squeeze every bit of power and efficiency out of the engine, drivetrain, body.......everything. Any add-on doodads are more likely to decrease fuel efficiency. If they do add, then it will likely be under a very specific conditions created in a lab.