Modifying your own save files for personal use is generally legal. However, using edited saves to gain unfair advantages in online multiplayer (e.g., CoD or GTA V) can lead to PSN bans. Bruteforce Save Data itself is a tool—your actions define the legality.
: Allows users to change the Title ID of a save, making it compatible with different regional versions of a game (e.g., converting a US save to a European one). Ps3 Bruteforce Save Data 4.7.4 Download
Access and modify protected save files . Modifying your own save files for personal use