Oscar, I suggest trying the latest mods released as they improve the game 100% already, but itīs still a long hard road to raise this game to an epic level like SH3.
The modders are doing some GREAT work, some are even starting fidling with the campaign files to add and alter several things, and I bet some are trying to build a more realistic form scratch.
Here, take a look by yourself:
http://www.subsim.com/radioroom/showthread.php?t=162013
Happy Hunting =D