And, you don't have to unhook the battery either. If you DO unhook the battery, the truck's PCM will have to "relearn" it's idle and fuel trim strategies. This has been recommended by some if you do some serious modification that can effect the fuel mixture, such as installing a CAI.
Ultimately, I think, the PCM learns to cope with the new modification even if you didn't disconnect the battery, but disconnecting it speeds up the process (and forces you to reset your clock and radio presets).
But, leave the battery connected when installing your Gryphon or after programming the PCM.
The changes you make to the PCM are instantaneous. Once the programming is complete, you're good to go. Programming takes anywhere from about 30 sec up to several minutes depending on what you decide to do about Custom Options". You can read about Custom Options in the manual.
- Jack