We have decided to update the ruleset for individual level runs (Road rules, Bike events, Burning Routes, etc.) to cover use of external mods for quality of life improvements. This is not a change, but rather an adjustment to reflect the way mods currently are being used by the community and have been used historically, and we wanted to ensure we have a position on this that is properly reflected in the rules. This is not a new restriction, but rather the opposite.
To see the new addition, you can view the rules in either of the individual level categories, most importantly "No Traffic" and "Any Glitch". Basically, our goal is to allow players on PC to skip the rather tedious process of setting up the glitches and make these IL categories more accessible. This does of course not mean we open the flood gates to unrestricted mod use, but instead the mod use should be treated the same way as setting up a glitch would be. It should happen only before the run starts, and it should happen only to achieve setups that are possible to achieve within a vanilla, official version of the game (e.g. both car in bike event AND no traffic is not possible without mods, therefore runs with it are not allowed).
If you have any questions or find a problem with the new addition to the rules, please reach out to Burninrubber, themorgue or me.