Interestingly, the Manufacturers final race has Hard and Medium tires both as required, but not Soft. It also states that dynamic weather will be on. Will the teams have to figure out how to fit 2 mandatory dry tires around rain? That could get "interesting"... It also, interestingly, has "Custom" slipstream (surely not the nonexistent slipstream used in qualifying sessions?) and unannounced multipliers.
The Nations finals has S/M/H mandatory as normal with conditions specified as "Fine". Although it also has the Custom slipstream. Maybe they're testing some changes to dirty air or something?
Also, all of the competitors now have profiles here
https://www.gran-turismo.com/us/gt7/events/gtws2023/showdown/competitors/, including ratings out of 100...