One of the main reasons for Need For Madnes's popularity is its comparative ease to hack, that is, to make custom levels, cars, models, and even game elements. The game must be downloaded to hack it.
It is always recommended to make a backup of your original data in case you break something.
Hacking Tracks[]
The tracks are stored in text files, which can be opened with any plain text editor. Formatted programs like MSWord are NOT recommended.
For detailed instructions, see Hacking Tracks.
Hacking Cars[]
The cars are defined by .rad files that contain text, but that codes for their color and shape. These files can be found by renaming /graphics/models.zipo to ...".zip" and then extracting them. To be read by the game, however, they must then be repacked into that zip folder, which in turn must be renamed back to a .zipo.
For detail on actual editing, see Hacking Cars.
Hacking Track Pieces[]
Track pieces can be hacked in the same way cars are. See Hacking Track Items for details.
Hacking Images[]
Many of the game images are stores in four .zipo files - in the same place where models.zipo is - which can be extracted, edited, and repacked much like car files. Most of the images are in GIF format.
Hacking Music[]
All of the music is stored in zipo files in the "music" folder. Extract them the way you would any other .zipo. Each song is in a separate zipo. It is generally inadvisable to try to edit the music; swapping pieces will cause tempo distortions, as the game sets what speed to play each music at. More, since the music is in .mod form - a sort of hybrid between MIDI and digital audio like mp3 and wav - it is very difficult to edit. The file consists of arrays "patterns", which in turn are a series of orders to play audio samples at a given pitch. As many of the samples are themselves unmelodic or multiple pitches simultaneously, going between .mod and any third-party music is a nightmarish amount of work.
Hacking Scripts[]
This is the most powerful but also most difficult kind of hacking. It requires decompiling mad.jar and editing some of the Java code itself. This requires a special editor like NetBeans and a skilled, knowledgeable user. Do not attempt unless you know what you are doing.
Done right, this can be used to change car names, statistics, add cars and tracks, change game behavior, and alter various items. However, it cannot change "fundamental" traits. For example, you cannot turn Need For Madness into a multiplayer by editing mad.jar.
For detailed instructions, see Hacking Scripts.