For anyone who is still here and doesn't know what we're talking about...
cfg files:
user.cfg is a text file in your MWO install folder. You can place the names of game settings and associated values into this text file to change those settings. Some of the settings are not otherwise available. The file is originally empty, and it is
intended to allow the user to make changes to settings.
system.cfg is a similar file with similar content, which will be full of the settings you've chosen (and other implicit settings based on those choices) for your game's video and audio settings. Feel free to open it in Notepad (no fancy software needed) or any other text editor if you want to look at it.
FoV:
FoV is not a hack. It is a setting in every 3D engine which is made available to the user (either directly within the game or from config files) in every FPS game I can think of. It gives you more peripheral vision, but at the cost of
reduced size of things in front of you (since they appear to be "further away")
. It makes it
harder to hit targets that are in front of you, particularly at distance. At higher levels, the fisheye distortion this causes negates the benefit of the peripheral vision (particularly in a game where part of your peripheral vision is that of a cockpit wall).
It's a setting based on personal preference, nothing more.
To change it, simply add the line "cl_fov = xx" (where xx is a number to change it to. 80 is a good starting value) to user.cfg.
Clearing up Night and Thermal Vision:
This is also achieved by modifying user.cfg. The most noticeable options changed are those which control the brightness and the blending noise in those views - i.e. the fuzzy edges when moving. This makes night and thermal vision clearer, which does give some degree of an advantage - but nothing particularly major, really.
It has
no effect on the draw distance (how far away mechs are before they stop appearing) in those views.
See
this thread for details on how to make the changes.
Film Grain removal:
Normally removed by substituting a texture file so that the mostly transparent "noise" image is replaced by a fully transparent image. It simply makes the game look a little bit cleaner / less gritty in general play. The effect is almost entirely aesthetic - It does not give you any advantage other than making the game a bit easier on the eyes.
If you want to do this, follow the instructions
here. It simply involves downloading a zip file containing the appropriate folder structure and texture file, and extracting it into the game directory.
Other Changes:
There is potential for numerous other changes that could give people an advantage, but to my knowledge this is not widely done or known about. The film grain removal technique is the basis of how this tends to work:
The game folder contains ".pak" files, which are just archives (like .zip files) containing the game's assets - textures, models, data files, etc - all arranged into folders. By default, the game uses those files.
If you replicate a file name present in the pak files (and its location within the folders), the game will use that file instead of the one in the pak file.
This is not inherently an "exploit", but simply the way the engine is designed. It has been used to great effect in games like Skyrim - allowing people to replace textures and other files to make the game look a lot better, amongst other things.
In a single player game, this isn't a big deal - how you choose to make the game look/perform on your PC is your own business and effects nobody else.
In a multiplayer game, certain changes may give you an advantage over others and hence drama ensues.
Draw Distance & Depth of Field:
Draw distance determines how far away things (most importantly mechs, but also things like buildings) will be rendered at. e.g. you can see mechs (rendered in high detail) that are close to you, but when they are further away, they are rendered at lower detail, and further away still they are not rendered at all.
The game does this for the sole reason of performance. It takes more computer resources (primarily RAM, CPU and GPU) to keep lots of things on screen and in high detail, hence the further away they are the less detail they are rendered at and once they get far away enough they are not rendered at all.
The in game settings for object details (options > advanced options) influence this, but the main determining factor is how good your computer is. People with powerful computers will be able to crank this value and have things appear when they are futher away. This could be seen as giving them an advantage, but... well, suck it up. People buy expensive computers so they can play games with the settings maxed. They may also have a bigger monitor than you, surround sound and a more accurate mouse - all of these give them an advantage.
user.cfg settings to change/tweak draw distance are discussed
here. I'm not sure if this allows you to set values that exceed what the game sets at high specs, but if you're on lower specs and find that mechs only appear when closer than you'd like, you could try playing with those settings. It won't magically make your PC more powerful though, so you may need to turn down some other options to accommodate for it.
Depth of field blurs things in the distance, which some people don't like. It can be disabled either by turning down the "Post Processing" slider in the game options (which I believe may also turn off some other effects such as HDR) or adding "r_DepthOfField = 0" to user.cfg.