The CAPA flash tuner is the way to go.
You can buy these and do it yourself and you will get 2 tunes with the kit.
One tune is an 8psi boost and the other is 10psi.
To get the most from them ,then you can get a custom tune done with the CAPA flash tuner but it is not absolutely needed.
It arrives in a box and you simply follow the instructions to download the factory tune to the box and upload the new tune. If you take the car to Ford for servicing ,then you MUST reflash back to the standard tune before taking the car in for service.
There is a CAPA area on the forum but you may need to look further back for more info.
http://www.fordforums.com/forumdisplay.php?f=662
It is simply plug and play with no alteration to wiring or anything and I'm sure this is what you are looking for. If you want more power later then you can get a custom tune with other mods and go as far as you like using the flasher for the tuning.
As a first step just using the tunes that come with the unit are enough with no other mods needed then as you want more power you get better tunes with the correct mods such as injectors, valve springs ,fuel pump etc added to cope with the higher power lvls.
Very recommended by many.