Unless you are looking to go VERY LOW, why don't you just go to your loca Ford dealer, and buy a set of EL XR springs ?
King springs loose their tension after a couple of years as do other brands, but the EL XR springs are magic. I know i've tried 3 sets.
Also, definitely spend the money & get the adjustable Koni's, that way you can set up the firmness/rebound rate the way you like.
An extra inch or so may look cooler, but handling may actualy suffer, let alone the guard scraping, bottoming out impractability side.
For better handling, get either the EL XR8 rear sway bar, or visit the WHITELINE AUTOMOTIVE site and order thier adjustable front / rear sway bar kits, not to mention their nylon camber kit.