Other visual tweaks, better trees, texture packs and cars
For a more consistent and believable day/night cycle, as well as some non-ENB shader tweaks, consider installing the RealityIV 1.62 Timecycle Mod . Once you have ENB and RealityIV working in tandem, complete the package with some high resolution textures courtesy of the Better City Textures pack . The crisp lighting and shaders pick out the extra detail in those road surfaces perfectly, and is certainly worth a performance hit if you've got a powerful set-up.
There are a few nice but minor updates to be made once you've got the major graphical mods in place. TreesModIV overworks GTA's tree textures. Add this bus to improves the authenticity of those Big Apple traffic jams. The Viva New York mod below takes care of taxis, subways and Time Square. For custom cars, browse GTA 4 mods extensive list. There are some gems in there. I like the Formula One Ferrari and this VTOL jet but it's all a matter of taste. Whatever cars you add, spawn them at will using Blade's Vehicle Selector .
NB: There's a very common bug that might pop up as you're installing vehicle which turns all of the cars in Liberty City into taxis. Fix that with Chikamru's Real Traffic tweak .
Viva New York
Oh, Liberty City, we all know you're New York. The comedy billboards Rockstar used to dodge legal trouble were amusing for a while, but after ten or so hours of adventuring the jokes grow old. Viva New York patches up Liberty City's subways and taxis to make them look like their Big Apple counterparts and transforms Times Square with accurate billboards and scrolling neon ads. It's all there, glowing signs for Coke, Pepsi, the NASDAQ building and never-ending runs of The Lion King and Phantom of the Opera.
More realism mods: fuel, cautious drivers and first person mods
Now we've got a beautiful, detailed facsimile of New York to explore. If you want more realism from the city there mods out there happy to oblige. There are a few first person mods about, which do exactly as you'd expect. If you run your car into something at high speed, the hit might pop you out of Nico's head for a split second, but otherwise they're well implemented, and do a great job of bringing you down into the streets.
Does it bother you that Liberty City citizens drive around with their cars unlocked waiting for you to steal them? Cautious drivers will fix that behavioural quirk. Does it bother you that cars have infinite fuel and never need a refill? Grab the fuel mod . Real shop fronts spices up commercial districts with some authentic store retextures and this bank account mod lets you use ATM machines to deposit and withdraw money and earn interest.
This is a good 'un. If you're hungering for a little extra kersplode from your destructive sprees in GTA then the Bigger and More Realistic Explosion Mod is what you need. I wouldn't say the resulting fireballs were more realistic exactly, but they are certainly more satisfying by a factor of several Die Hards. Installation is a simple drag 'n drop task. Head to your GTA folder, go into Common -> Data -> Effects and then replace the explosionFx file with the modded version. You might want to back the old file in case the new one SUPER EXPLODES.
Hit the final page to see how to cheat, change the laws of physics, become a cop or Hulk-out.