Also, is there a nice guide out there to get someone up to speed on how to get GTA IV modded optimally? I've seen a few ENBs but are there texture improvements? Improved models? New cars? Etc etc? I've never played that game more than 30 minutes because my computer used to run it like crap WITHOUT ENB. Times have changed =)
Sethos has a guide
HERE.
There are a ton of ENB's out there right now, can be hard to pick a nice one to use (imo, a lot of them are crap)
I use Schakusa 3.0 ENB. Schakusa offers a "main file" which includes DoF and AO, and a "medium-spec" file that gets rid of DoF and AO for more FPS.
This ENB uses SweetFX for SMAA and to tweak the colors a tiny bit, but he also includes a non-SweetFX version (i know some people don't like SweetFX... so I think its a nice option to include)
There are road and tree texture mods included in this ENB too.
As for textures, there's mods for just about everything... buildings, roads, trees, billboards, signs, character models, npc's, weapons, etc... You can go
HERE to check some of them out.