Most pre-packaged "mod-friendly" archives come with the 4GB patch pre-applied, allowing the game to use more RAM without crashing when you install high-res textures.
The choice of the .7z format is itself significant. In the mid-2000s, most mods were distributed as .zip or .rar files. But San Andreas mods grew enormous. A single high-poly car model with custom textures could be 5 MB. A total conversion replacing all vehicles, weapons, and peds could exceed 2 GB uncompressed. The .7z format, using LZMA (Lempel-Ziv-Markov chain algorithm), offered 30-50% better compression than ZIP. A mod-friendly base installation of San Andreas (the game itself plus all foundational tools) typically shrinks from ~4.7 GB to under 2.2 GB in a well-made .7z . This was critical for early file-sharing forums with upload limits and slow broadband connections. Grand-Theft-Auto-San-Andreas-Mod-Friendly.7z