Rocmoc, this should help for carbuerated models but not for EFI units. I think it allows air/fuel mixture to travel a little further before entering combustion chamber, allowing for better mixing and better combustion. Some spacers can even add a swirl effect to incoming air/fuel mix. Good luck!
FYI...Check this out!
$69 Car Performance Chips
60 Horsepower Increase Save 7 MPG Easy Installation on All Cars
www.GFChips.com
This ad came from page you linked to. I have tried on of the units on my ex-2008 Toyota FJ to impressive results. Noticed more responsive throttle, more power overall, especially towing, and 2+ more mpg! I just got an 06 F150 and ordered new chip today. I hope it works as well as last time. I emailed GForce and asked if they could supply upgrade for our Troopers. I will let you know what the say.