There are two types of mods for C:R: CarMODgeddon mods and ZAD mods. Both types of mods are similar but there is a key difference between them:

• ZAD mods can change pretty much anything about the game, but have the downside of being unsupported officially and trigger the game's cheat protection which locks out multiplayer and stops career mode from saving. ZAD mods affect the whole game and have the potential to require a reinstall to return the game to an unmodded state if they are mishandled. ZAD mods have the file extension of .ZAD.
  
• CarMODgeddon mods are the officially supported method of modding the game and work in multiplayer when launching the game in CarMODgeddon mode, but are currently limited to cars, wheels and levels, though there are plans to expand this at a later date. CarMODgeddon mods run in a sandbox mode and do not affect the standard game at all, they only show up in CarMODgeddon mode. CarMODgeddon mods have the file extension of .ZIP.

CarMODgeddon is a sandbox mode which immediately gives you access to all the game's content and lets you run supported mods freely and use them in multiplayer.

There are three methods of launching the game in CarMODgeddon mode:

1. When you launch the game from Steam you get the following prompt, select "Launch CarMODgeddon mode" and click Play:
   
   
2. If you use the Minge mod installer tool then you can click Game Options, tick Enable CarMODgeddon and every time you start the game through Minge it will launch straight into CarMODgeddon mode:
   
3. If you use a shortcut to launch the game then you can add -carmodgeddon to the command line ot launch into CarMODgeddon mode.

The easiest way to use CarMODgeddon mods is to grab a tool called Minge from http://carmatools.com/Tools/Minge. CarMODgeddon ZIP files can just be dragged and dropped onto the tool and it will bring up an installation prompt which will automatically place the ZIP files into the correct locations.
Note: that sometimes CarMODgeddon mod ZIP files are distributed inside other ZIP files in order to distribute wheels with the associated cars, in this case you will need to extract the contents of the distribute ZIP and drop the enclosed ZIP files onto Minge. An upcoming update to Minge will have a better method of handling bundles of mods.

After you have installed the mods you will now need to activate them by clicking on the tick boxes by their names in the list and clicking Save. This creates the configuration file telling the game what mods to use. With the mods installed and enabled you can start the game in CarMODgeddon mode and the enabled cars and levels will show up in the garage/level select.

Currently CarMODgeddon has an issue where everyone in a multiplayer game needs the exact same mods enabled. If you have an extra level or wheel or car enabled which the other players do not then it won't let you join the same game, even if those mods aren't actually used. Before you start a CarMODgeddon multiplayer game you need to organise what mods you will use with the other players and disable the rest of your mods from Minge. This is very combersome and annoying but we have been assured it will be fixed at a later date when Stainless can put their resources into developing CarMODgeddon further.

To use ZAD mods you just place the ZAD file inside the game's ZAD folder. A word of warning, though, DO NOT EVER overwrite or alter the game's original ZAD files. It not only makes it unable to be restored to an unmodded state without either redownloading the game's data or restoring from a backup, but it also has the potential to break any future updates to the game as Steam may not replace the modded ZAD with the updated official ones.

If you're using ZAD mods then make sure the ZAD files you are installing have a different file name to the original ZADs and start with the letter Z. The game loads ZAD files in alphabetical order, so ZAD files starting with Z are loaded after all the official ZAD files and the files inside of them is used instead of the corresponding files in the official ZAD files. This avoids the aformentioned issues with restoring to an unmodded state as all the mod ZAD files are clearly marked and can easily be removed and it also avoids the update issues. You still have to be careful as the mods may be based on old data and miss out on improvements and new features. For example, Psygery released a game balance mod but if an update changes the balance script you won't see those changes until you remove Psygery's mod's ZAD.

You also have to be careful with older ZAD mods because a lot has changed with the way the game is structured since the Pre-Alpha and many early mods will not work in the best case or will crash the game entirely in the worst case.

Career mode is intrinsically linked to the leaderboards and stats on Steam, which Stainless want to keep competitive and fair. If they allowed career mode to save when ZAD mods are used then it would allow someone to very easily create a mod which gives them many billions of credits for each kill and kills all peds and opponents instantly, among other such cheats, which would completely ruin the stats and leaderboards.

The best place to get mods from is the Modding section of the official Carmageddon forums here: http://www.carmageddon.com/forums/modding/carmageddon-reincarnation

You can look through the various threads there to find numerous mods. Here are some threads to pay attention to:

• Mad Mike's Used Cars[www.carmageddon.com] - Mad Mike has released a load of muscle cars, some heavyweight vehicls and a few remakes of old Carma cars. He's a modding machine, combing a great knowledge of car mechanics, 3d art and technical understanding of how to set up the game's cars. He has 14 cars released so far.
  
• Fat Cat's Modding[www.carmageddon.com] - FatCat is a superb artist and is improving his technical understanding with each mod he has released. He has 5 CarMODgeddon compatible cars released so far and is working on more.
  
• Alex's Garage[www.carmageddon.com] - AlexTSK's (formerly Bloodstability) skills are insane, a top class artist. He only has one CarMODgeddon mod released so far but has a number of work in progress cars.
  
• Carmageddon 1 Cars[www.carmageddon.com] - All the cars from Carmageddon 1 ported to C:R. I'm working an update to the pack and I'm working on updating the C1 levels pack I released for the pre-alpha to the full version.
  
• Dr. Fraginton is on the Right Track[www.carmageddon.com] - A half-track proof-of-concept by Doctor Fraginton. He is also working on some other mods such as a remake of Sweettooth's truck from Twisted Metal[www.carmageddon.com].

Again, you can get ZAD mods from the official modding forum. A couple of interesting ones are:

• Psyrgery's game balancing mod[www.carmageddon.com] which changes the balance of the game
  
• My UI mod to re-enable the pre-alpha freeplay cheats & driver picker[www.carmageddon.com].

To start with cars and levels are made in 3D software like Blender, Maya or 3D Studio Max and textures are made in any image software such as Photoshop or Gimp. You also need text editing software such as Notepad, Sublime or Notepad++ to edit the scripts, materials and general paperwork files which go along with the models and textures.

There are currently two main tools for converting models into the correct format for the game:

• Flummery[flummery.co.uk] by Errol, an open source spriritual successor to Carma 2's Plaything2. It's still work in progress but it is usuable. Errol has done amazing work with it so far. He has updates planned for it.
  
• Carmageddon: Reincarnation MaxScript Tools[carmatools.com] is a set of scripts I wrote for 3DSMax which can be used to export models to C:R as well as configure a lot of parts for the car, including moving parts, suspension, etc. My development version has basic support for ped models and animation exporting and level tools such as accessory placement and opponent paths, as well as support for the new tech features such as tank tracks and more than 4 wheels.

When you export from Flummery or my MaxScript tools you can convert the associated textures automatically or you can use a version of GibbedTools which I modified to support C:R which you can grab here: http://carmatools.com/Tools/GibbedTools

Some other tools are:

• Carmagedon Ultimate Node Tool[carmatools.com] - A tool for manipulating .CNT files, which define the hierarchy and positioning of parts of a model. Handy for inspecting CNT files to see if something is wrong, using as reference for creating Structure..XML files for cars or for rearranging the hierarchy of a model without having to use a heavyweight tool like Flummery or 3DSMax.
  
• LOLDecoder[carmatools.com] - A tool for decompiling the the game's LOL/LUA scripts. Based off UNLUAC. Slightly obsolete as Minge now supports either decompiling all the scripts in the game's Data_Core folder structure if you've extracted the game's data or individual scripts if you drag and drop them onto Minge. The standalone tool can still be useful though.
  
• ZADF*cker[carmatools.com] - A tool for extracting the game's ZAD data files into the correct location to run the game on extracted data using the -disable_zads command line option. Completely obsolete as I have now implemented it into Minge.
  
• VTF*cker[www.carmageddon.com] - an unreleased WIP tool I am working on for browsing the game's Virtual Texture packages, extracting textures, replacing textures and creating entirely new Virtual Texture packages for mod levels. Currently I have the first three features working and am working on the fourth. Release is hopefully coming soon.

There are a few tutorials in various threads on the official modding forums, one of particular note is Mad Mike's extensive tutorial series on using my MaxScript tools[www.carmageddon.com] and AlexTSK has done an FAQ & Problem solving[www.carmageddon.com] thread and started on a tutorial series[www.carmageddon.com]. There is a lot scattered information through out the modding forum and you can ask any questions you have there there. I have a few tutorials under way but I am currently focussing on tool creation right now.