This tool translates GameShark codes for the PlayStation game Gran Turismo 2 (Gran Turismo/Simulation Mode disc) between NTSC-U 1.0, NTSC-U 1.1, NTSC-U 1.2, PAL, and NTSC-J versions.
The JavaScript code is a refactored and reissued version of the original code which was previously available on this archived page.
You can use the tool here.