The editor allows you to edit the character's HP, SP, stats, experience, level, name (P3 and P4 MCs only), the inventory, the key items inventory and the gold.
There's also a feature to completely fill the Enepedia and another to replace all currently equipped weapons and armours with the best ones for each character.
Extracting the save
Persona Q Save Editor
There's also a feature to completely fill the Enepedia and another to replace all currently equipped weapons and armours with the best ones for each character.
Extracting the save
Warning: Spoilers inside!
Persona Q Save Editor