The ruleset was created only with the Japanese version in mind at that point. I'm fairly sure that the japanese audio DLC would ultimately be allowed to use as the only DLC. About all the other DLC, including costumes. The Problem is that on PS4 you can't uninstall specific DLC and it will automatically download all owned DLC when downloading the game from PSN. Certain DLC costumes come with accessories that do in fact heavily influence the run, such as nullifying elements, increasing EXP/Money gain, etc. Therefore, at least for now, DLC is banned entirely. The DLC is stored in a box in your room, as long as it's not inspected you won't actually acquire the DLC items, aside from Persona DLC which is always in your compendium, if you own the 20th anniversary edition for example. Needless to say that these Persona can't be bought from the compendium, or used in general in a Speedrun.