If you need a very small, legal, retro-style GTA experience instead, consider:
In the scene (the non-pirate discussion, just the tech), specific groups are famous for high-quality compression. For GTA: Vice City, look for releases tagged by: highly compressed pc games gta vice city best
The compressed version needs the "Vice City Save Game Editor." Open it, load your save, and just click "Save" again to re-calculate the checksum. If you need a very small, legal, retro-style