If you plan to stay naturally aspirated (no turbo or supercharger) then there is very little difference between the three you listed. Stillen seems to be the most popular, followed by the JWT pop-charger. I have only seen a couple weapon-r intakes installed. I wouldn't bank on any customer service from Weapon R while the other two actually have a service department and installation shops.
In terms of power gains, all three of them would benefit from having your ECU tuned, but I would do that only after you are finished with all intake & exhaust mods you might plan to do. Best thing for you to do is try to listen to each one installed to see what you like before deciding. Most of the change you get will come with the sound of the motor... maybe just a bit more response.
