From me: "The most (I'm not afraid of this word) most realistic setting for ENB Series for GTA IV" - from jumper_311.
From the author: "I didn't use anything special, my setup uses one of the best iCEnhancer version 2 settings, I tried very hard to set up iCEnhancer (and I did it)".
Naturally, this is not his last setting. The setting goes both to the 1.0.3.0 version of the patch, and to 1.0.4.0
Tested on good PC: Intel 2700k DDR3 1600 16G GTX 670 2G Intel SSD 335 240G