As someone who played both PS2 and PC version of the game know, there were some missing or cut features in PC that was in PS2 version. Something is possible to fix or at least replace it, some other features aren't that easy.
I know that PS2 and PC(Xbox) has different engine builds, but is it able to fix it by modding the game?
List of cut or missing effects in PC:Certain vehicles like the Dodo and Uranus lack this sheen, causing them to look dark compared to other vehicles.Several parked vehicles were removed on PC.Cars are always dirty. (Fixed in 1.1 version)Moon displays no phases.Trucks like the Linerunner, Yosemite and Tanker's dual rear wheels were glitched and somehow doesn't displays.Incorrect lighting of the environment, causing everything to look darker than it is. (Fixable by replacing PC timecyc by PS2 one.)Parachute object animation is displayed incorrectly, making it look static no matter how the player moves. (Fixable by installing other parachute mods.)The decals on many vehicles like the Sandking and Bloodring Banger do not display correctly.
Shady Industries were renamed to Solarin Industries. (Can be easily fixable by replacing textures)Helicopter, and airplanes that had blurry rotors and propellers were cut on PC. (Maybe you could bring it back using some codes?)Some objects near Four Dragon Casino are missing on PC.Some npc paths are missing on PC. (Zero RC shop, near SF Gant Bridge) (Fixable by adding more paths)The 'trails' effect which made the game to look more colorful was cut on PC. (Don't know why, it was gone entirely. Rockstar must have hated this effect.)Sun looked much bigger and brighter in PS2 then in PC. (Similar to Vice City one.)Lens Flare effect is different from PC and PS2. (PS2 one is intense.)There is rendering issue on certain alpha textures in PC. (Vegetation, and some of the alpha textures. This is an engine bug which is most likely not fixable)'Reflection' looks more intense on PS2. (Fixable by using SAGFX.)Cars in cutscene 'twiches' in PC. (Not sure)