The final version of popular Grand Theft Auto 4 mod iCEnhancer has been released; download version 2.1 at the source.
Unfortunately only a version without an installer is available at the moment, so you'll have to go through this tedious process if you want to make use of it immediately. For those who can't be bothered, an installer version as well as the 1070/EFLC version -- the only one which should be used with the Steam version -- should be available today or very soon after.
If you're unfamiliar with iCEnhancer, it vastly improves the graphics in Grand Theft Auto 4. Check the latest video on it below, which at times can be hard to distinguish from real life.