Just went down a rabbit hole thinking about the old PSPisoClub days. There was this mysterious "GTA 4 Exclusive" thread back around 2009–2010 — people claimed it was a modded/beta version of GTA IV ported to PSP or a special PC repack with exclusive content.
Sites offering "exclusive" or "highly compressed" ISO files often bundle them with unwanted software or malware. Verified GTA Titles for PSP pspisoclub+gta+4+exclusive
[internal link – member-only section]
If you want to experience the closest thing to this "exclusive" community content, you will need a PSP with Custom Firmware (CFW). Just went down a rabbit hole thinking about