An online test version was released through Playstation Underground about a year after the final release. It started the player off with 110 million credits and all the cars in the Gran Turismo Mode, alongside the online capabilities.
Contributed by whitemex0721
Gran Turismo 4 was one of four PlayStation 2 titles released that could support 1080i HD, through the use of component cables.
Contributed by KnowledgeBase