Here are some basics you need to know.


If not done already set your Windows to show file extensions, so that you clearly see what files you are dealing with in the game folder and beyond. Also it's better for your security, read the linked article explaining why and how do to it:
https://www.howtogeek.com/205086/beginner-how-to-make-windows-show-file-extensions/


The game is located at:
"your steam library folder"\steamapps\common\Street Legal Racing Redline

To find "your steam library" folder go to:
Steam > Settings > Downloads >STEAM LIBRARY FOLDERS

To get to the game directory quickly:
in your steam library right-click on "Street Legal Racing: Redline 2.3.1",
click on "Properties...",
then click on "LOCAL FILES" tab,
and then click on "BROWSE LOCAL FILES" button

Even quickier:
right-click on "Street Legal Racing: Redline 2.3.1",
"Manage"->"Browse local files"


Your saves are in the game folder at \save\career
If you used the "save car" menu entry in game, the files are in "SLRR folder"\save\cars (ignore the folders in there)
When restoring save backups, note that if the save was created when using mods, this save may cause a game crash if the used mods are not installed.
Here is a guide about save files
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1521971991

Before verifying the files, uninstall all mods first. In case you verifyed with mods installed - uninstall them and verify again.

Steps:

1. open "Properties..."->"Local Files" tab (as described above)
   
2. click on "Verify Integrity of Game Files..." button

Note: after doing this the game settings will reset.


When reinstalling there is no need to uninstall or unsubscribe mods.

Steps:

1. delete the game folder (important step!)
   
2. right click on "Street Legal Racing: Redline 2.3.1" in steam library,
   click "Manage"->"Uninstall"
   
3. install the game
   
4. verify the files

And at last run the "class remover" feature of the Custom Workshop Installer.

1. subscribe to the Custom Workshop Installer and read its description
   
2. install and open it - as described in "Usage" section
   
3. run the class remover

Tipp: now backup the game folder to avoid redownloading the game in case you need to reinstall again.



Further reading
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2195070614