1.custom firmware is basically the same as official firmware but with unlocked addons/abilities,so its more advanced than the ofw counterpart
2.pandora is a hacked battery(hardmod or softmod via a cfw enabled psp or a device tool) that turns the psp to service mode so that you can install custom firmware for the first time and recover bricked psps.a magic memory stick is special files on your stick to work with the pandora in order to get the custom firmware flashed onto your system
3.this can be free if you follow my guide(1st link of my signature) but be careful when hardmodding your own battery into a pandora,no programs really required but whats in the link i mentioned on my signature.
4.if you follow all ive already said,you can easily use this and only this to get custom firmware.if you have any questions ask
