One of the main reasons intake and exhaust modifications are so popular is the generally accepted belief that stock intake and exhaust systems are restrictive relative to what the engine in stock form can actually use. The generally accepted reasoning that OEM has this in place ranges from manufacturing cost savings and emission requirements to marketing intent and product life expectancy. There has been a long standing debate between whether lots of hot air is any different than relatively less colder air. As with most things in the automotive performance world, its all linked together and it has to be established what an engine in its current form really needs for air and fuel. To make more power you need more fuel, to properly burn that fuel you need the right amount of air. Increasing one without knowing if the other needs change is a job half done.
Also, beware of the butt-o-meter, its accuracy is obscured by the sound-o-meter and the spiffy-new guage. Just think of all those little cars running around with coffee can mufflers with the butt-o-meters reading way off reality.
What would be interesting is to find some kind of base line tests of your own. Something I should have done one of these times. Take and pull a load up a given challenging hill with the stock intake, take note of how fast you are going and at what rpm. If you have pyrometer, trans temp (if an auto) and maybe engine temp guages, take note of what they say. Burn through a couple tanks of fuel on a commonly used route like to and from work then record your mileage. Then swap in your modification of choice and repeat. Compare the results. Facts will help calibrate the butt-o-meter and the results will let you know how you did.
At the end of the day, its your truck to do with what you want. I have done the same as yourself many many times because tinkering with your truck or car is just fun. The possibility of finding an inexpensive upgrade to uncover some power lost at the drawing board is exciting. Just don't rely too heavy on what you see for online test results, chances are you are not being given the whole picture.