Bad news is, I have added several different textures mods since getting the game at launch and are now not quite sure what is installed...
Good news is, I know what, by far, the most important mods are:
ENBseries mod 0.079SORA (changes the graphics enormously and enables SSAA, SSAO and SSIL)
and
First Person v1.1 (allows you to play in first person view).
I am driving around with a wheel (Logitech G25) and walking around in first-person view (xbox360 controller), and it is mindblowingly atmospheric.
It really feels like like a living, breathing city.
The biggest problem is performance (10-30 fps). With these mods, the game requires a very fast quad core CPU and a >1GB VRAM card to truly be the game it always should have been.