After three days of trying to figure out how to fix my game after corrupting it with mods, I found a solution...
1. Uninstall SLRR
2. Delete SLRR directory (the folder that says Stree Legal Racing Redline in your steamapps\common\ folder. (C:\Program Files (x86)\Steam\steamapps\common\Street Legal Racing Redline)
3. Go to your steam client, click Steam (top left-hand corner), go to settings, go to downloads, click "Clear Download Cache". Your steam client will restart itself and you'll have to log back in.
4. Reinstall SLRR
5. Go back and check all your mods and make sure they're all for the most current version of the game. There's a filter on the workshop for this. Uninstall the ones that aren't up to date.
6. Double check each mod comment section and see if it's working for others.
7. You can reinstall all your mods again one by one, testing the game after each install, or reinstall all of them at once and hope for the best. You may end up having to repeat this 7 step guide. (RIP)

My game is currently modded up and still working. Had quite a few issues with sparky's editor but found a solution online. This will be in another discussion titled "FIX Redline Car Editor By Sparky (crashes using Sparkys SLRR editor 2)"